Annual Report 2009 – 2010

Raman Research Institute Bangalore Scientificff research is first andd foremost an expressiexpressiono of the resurgence of the humanman spirit in its search ffor self-expression. It cientific research is first and representsresentsforemostS an theexpression response of the resurgence of theof ththe human spirit in its search for self-expression. It represents the response of the mind of man to mindthe marvellous of and man ever-changing to panorama the of Nature. marvellousmarvellous– C V Ramanand ever- changing panorama of

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Introduction From the Director ...... 6

About the Institute History ...... 7 RRI at a Glance ...... 11

Areas of Research Astronomy and Astrophysics Overview ...... 14

Ongoing Research ...... 20 ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

Light and Matter Physics Overview ...... 30 Ongoing Research ...... 34

Soft Condensed Matter Overview ...... 40 Ongoing Research ...... 45

Theoretical Physics Overview ...... 56 Ongoing Research ...... 59

Facilities ...... 65

Academic Programs ...... 70

People at RRI ...... 72

Publications ...... 84

Other Activities ...... 85

Appendices ...... 89

Statement of Accounts ...... 133 ○○○○○○○○○○○○○○○○○○○○○○○○○○○○

he Annual report of the Raman Research Institute for the year 2009-10 is a summary of the research and academic activities of Tthe Institute during the year. The Annual report presents synopses of the ongoing knowledge creation activities in the different research groups, many of which have outcomes in the form of publications in refereed scientific journals. The Institute considers the transmission of knowledge an important activity; this

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from the Director students from all over the ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ country visit the Institute for stays ranging from a few weeks to several months and participate in the many research activities of the Institute. Communications of the ongoing research and also a sharing of knowledge of current research – in professional talks given by members of the Institute in conferences and in external institutions as well as Journal Review talks at the Institute – is another aspect of our knowledge diffusion. A cultural function of a premier research institute is the upholding and promotion of academic traditions and this includes the conduct of specialized seminars on technical topics targeted at specialized audiences as well as colloquia in a wider range of topics that are delivered in a style that strives to make current advances intelligible to a wider community. Additionally, outreach activities include writings intended for a lay and discerning audience as well as the delivery of motivational talks at educational institutions.

Included in this report are lists of publications in refereed journals, conference proceedings as well as in monographs, books and in popular periodicals, PhD degrees awarded during the period 01 April 2009 to 31 March 2010, as well as seminars and review meetings focussed on current research, which were held at the Institute. The report also lists the scientists who have visited the Institute from within India and from overseas during the period.

Bangalore Ravi Subrahmanyan August 31, 2010 Director

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Before jumping to the next pages in

search of the current exciting research activities conducted at the Institute, take a few moments to read about its history.

In between the collection of historical

facts you’ll discover a story about the ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

power of basic human curiosity – the invisible foundation on which the Raman

Research Institute was built and

managed by its founder Sir C V Raman

and subsequently by his successors. n 1934, while still the director of the Indian Institute of Science (IISc), Raman started Ithe Indian Academy of Sciences and attracted most of the best young scientists of that time, who published their work in world renowned journals of physics and chemistry. The same year the Maharajah of Mysore gifted to the Academy 11 acres of land in the north side of Bangalore. Few years later, Raman proposed that an independent research institute is built on that premises and an agreement with the Academy was signed. Raman embarked on a number of long journeys throughout the country to raise funds for the new institute. In 1943, the collected sum, along with his personal savings, was allotted for the construction of the first building. Its initial completion coincided with the retirement of Sir C V Raman from IISc in 1948 and in the beginning of 1949 he shifted all his activities there. The new center was named after its founder - Raman Research Institute.

From the very first moment of its foundation Raman undertook the management of his new institute with immense vigor and enthusiasm. He not only designed the main building with the help of an architect, but also took great interest in the arrangement of the whole premises. He planted trees, decorative bushes and flowers turning the barren land around into a beautiful garden. A walk in that garden

8 was an indispensable part of his daily life. The initial staff in the new institute consisted of four people including Raman himself. The lack of electricity during the first two years didn’t affect Raman’s thirst for knowledge and understanding the wonders of Nature. Great scientific work was carried out during these years using a few lenses and a manually operated heliostat. In order to support his staff and expand the scientific activities at RRI, Raman who was unwilling to take money from the Government, started a couple of chemical factories along with one of his former students. He used the profit to pay his staff and equip his laboratories. In the years to come, the institute kept expanding – soon there was a new library, few other buildings and a museum holding Raman’s personal collection of gems, crystals and minerals. Until his death in November 1970, Raman kept working tirelessly for the development and growth of the Raman Research Institute.

After his death, the Academy created a public charitable trust: the Raman Research Institute Trust. The lands, buildings, deposits, securities, bank deposits, moneys, laboratories, instruments, and all other movable and immovable properties held by the Academy for the Raman Research Institute were transferred to the RRI Trust. The foremost function of the RRI Trust was to maintain, conduct and sustain the Raman Research Institute. In 1972, the institute started receiving funds from the Department of Science and Technology of the Government of

India which, since then, has been its main

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Facing page: The RRI building during its construction in 1949; a group photograph taken at the Institute; the Nobel Ceremony where Raman was awarded the honour. This page (from top): C V Raman with Heisenberg; with Dirac; and giving lectures in the Institute labs and elsewhere

9 funding source. The same year, Venkatraman Radhakrishnan was invited to be the director of RRI. A renowned scientist himself, Radhakrishnan not only fulfilled C V Raman’s desire to build an observatory at RRI but formed a strong group in Astronomy and Astrophysics whose research work today is regarded highly worldwide. Until the mid 90s, the two main areas of research were Liquid Crystals and Astronomy and Astrophysics. The constant growth of the Institute and the expansion of the research interests of its members led to the establishment of two new groups – Theoretical Physics and Light and Matter Physics. The Liquid Crystal group was renamed to Soft Condensed Matter which conveys more accurately the diverse research activities of its members.

Today, RRI research faculty, scientific staff and students conduct active research in the above mentioned four scientific fields inspired by the

example of the founder – Sir C V Raman.

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On this page: C V Raman engages with visitors, students and children in the Institute during its early days.

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RRI at a glance

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Mission RRI is engaged in fundamental research in the areas of Astronomy, Astrophysics, Light and Matter physics, Soft Condensed Matter and Theoretical Physics as a part of the global endeavor of humanity to increase our knowledge and understand- ing of the world.

Director ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ The current director of the Raman Research Institute is Ravi Subrahmanyan.

Organization RRI is an autonomous research institute. The supreme body of RRI is the RRI Trust. The director is the chief executive and academic officer. The Governing Council is the executive body responsible for the administration and management of the Raman Research Institute. The financial matters are conducted by the Finance Committee at RRI.

Location RRI is located on a 22 acre plot in the north side of Bangalore City, the IT capital of India. It offers a quiet recluse from the bustling megapolis and a natural environ- ment which is highly conducive to cre- ative scientific work.

11 Research Areas Research, Scientific/Technical, Administrative Staff and PhD Students z Astronomy and Astrophysics z Research faculty: 39 z Light and Matter Physics z Scientific/Technical: 48 z Soft Condensed Matter z Administrative: 23 z Theoretical Physics z PhD Students: 57

Facilities 1. LABORATORIES

A&A SCM Radio Astronomy Labs: Chemistry Lab a. Digital Signal Processing (DSP) Lab Physical Measurements Lab b. RF and mm Wave Lab Liquid Crystal Display Lab c. X-ray Astronomy Lab Rheology and Light Scattering Lab LAMP X-Ray Diffraction Lab Quantum Optics Lab Biophysics Lab Laser Cooling and Light Propagation Lab Electrochemistry and Surface Science Lab Quantum Interactions Lab MECHANICAL ENGINEERING Non Linear Optics Lab Mechanical Workshop Laser-induced Plasma Lab Glass Blowing Facility

2. LIBRARY 3. COMPUTER FACILITIES 4. CAMPUS

Education RRI offers the following academic programs:

z PhD Program

z Post Doctoral Fellowship Programs

z Visiting Student Program

Funding RRI is funded by the De- partment of Science and technology, Government of India.

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AstronomyAstronomy ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ andand AstrophysicsAstrophysics Sir C V Raman could not fulfill his strong desire to build an astronomical observatory at the Raman Research Institute (RRI) within his lifetime. It was left to Radhakrishnan to do that. During the years Radhakrishnan served as the director of RRI, he worked tirelessly to establish a strong group of scientists and engineers in astronomy, astrophysics and astronomical instrumentation. Today, the Astronomy and Astrophysics (A&A) group at RRI is a collection of highly motivated, curious and open minded researchers who venture to explore the vastness of the Universe from its creation to its present state.

Currently, the A&A group consists of 27 members whose individual interests cover the areas of theoretical astrophysics, observational astronomy, astronomical instrumentation and signal processing. These are the four pillars on which the science of astronomy rests. Astrophysics concentrates on the development of analytical models and computational numerical simulations that try to describe the dynamics, physical properties and underlying phenomena of celestial objects (stars, planets, galaxies, interstellar medium, etc.) as well as answer fundamental questions about the formation and evolution of the Universe.

Observational astronomers “observe” the Universe with numerous telescopes built around the world covering large range of the electromagnetic spectrum – from low frequency radio waves to extremely energetic gamma rays. These observations are used to test existing theoretical models and give “food for thought” back to the astrophysics community. It is in the process of such interactions that the collective knowledge about our Universe accumulates.

Our own eyes deliver to us a beautiful but limited image of the outer space and ever since Galileo built his first telescope in 1609, these instruments have become our new “better” eyes for space observations. The instrumentation engineers at RRI construct telescopes to study celestial objects in overview

14 ASTROPHYSICS

Development of cosmological models – cosmology as a branch of astronomy is concerned with developing and testing physical models that try to explain the formation and evolution of the universe. Researchers at RRI are working on developing cosmological models describing the radiation from the epoch of reionization. The Epoch of Reionization (EOR) refers to the period in the early history of the universe during which the emergence of the first luminous sources (stars, galaxies, etc) ionized the predominantly different frequency bands, allowing neutral intergalactic medium. Such models will astronomers to peek into the most distant provide insight about the processes of corners of the universe back towards the time structure formation in the universe and answer of its creation. questions as to whether such radiation can be While creating the necessary academic detected with the currently existing environment for its group members to telescopes. conduct research in their field of specialization, Magnetohydrodynamic (MHD) Turbulence – RRI strongly encourages collaborations Turbulence in electrically conducting fluids is through various activities like coffee meetings, rarely observed here on Earth. However, in seminars, invited talks, colloquia, etc. This galaxies, clusters of galaxies and the interstellar often leads to joint pursuit of problems in medium, where matter is ionized, it is a theory and observations at institutional, widespread phenomenon. Researchers at RRI national and international level. The strong are actively working towards the development interactions with the members of the Radio of a comprehensive theoretical formulation of Astronomy Lab result in the development of a MHD turbulence. variety of astronomical instruments. These include stand-alone telescopes as well as Dynamo Theory – The astrophysics community special-purpose receivers that may add value at RRI conducts theoretical work towards to existing telescope facilities, and allow new understanding of the origins of large magnetic and specific astronomy research. Having strong fields around cosmic objects (stars, planets expertise and experience in the field of low- and galaxies) and the processes that sustain frequency astronomical instrumentation, RRI them. It is such magnetic fields that protect has expanded its activities to include the Earth from the solar wind of particles that instrumentation in mm wave and X-ray would otherwise destroy life on our planet as frequency bands. we know it today.

The following pages summarize the major Gravitational dynamics – The construction of areas of research for the Astronomy and models that describe the structure of the Astrophysics group. Each member’s individual orbits of cosmic bodies around black holes is work during the last year is provided in the another of RRI researchers’ goals. One of the next section, giving the reader more detailed ways of studying and observing the and technical description of their respective gravitational lensing (gravitational bending of research activities. light) predicted by Einstein, is through studying the orbits of stars close to massive black holes.

15 X-ray emission from radio galaxies – X-ray AGN are some of the questions that concern emissions from radio galaxies have been researchers at RRI. observed. RRI is working on developing a HI regions in the Milky Way interstellar medium theory which tries to explain the radio and X- – After the Big Bang some 13.7 billion years ray properties of such galaxies. ago hydrogen was created in great quantities in the Universe making it the basic building block of stars. The space between the stars is OBSERVATIONAL ASTRONOMY filled with neutral hydrogen at extremely low Gas clouds and winds from galaxies – RRI densities compared to the air we breath here studies the mechanisms of ejection of gas on Earth. The emissions from these hydrogen clouds from galaxies using observational data. regions called “HI regions” carries information about the conditions before star formation. Halo and relic radio sources – Clusters of Researchers at RRI look at the formation and galaxies are the largest structures of matter in structure of such HI regions using the Universe and understanding of their observational data from various radio formation, structure and dynamics can bring telescopes in India and abroad. an important insight about its evolution. Halos and relics are structures within a galaxy cluster Pulsars – The detection of pulsars was one of that emit strong radiation in the radio portion the serendipitous discoveries in astronomy. of the electromagnetic spectrum. Various Pulsars are known to be neutron stars, models exist that try to explain the origin of originating in supernovae, that spin very fast this radiation. Currently, researchers at RRI due to conservation of angular momentum compare observational data from Giant and periodically emit radio waves. Because of Metrewave Radio Telescope (GMRT) telescope their periodic emission, pulsars are often called with existing models and provide feedback to “the lighthouses of the Universe”. We can the astrophysics community. observe only these pulsars which beam in the direction of the Earth. Pulsar emissions provide Evolution and lifetime of AGN – Many of the insight about their structure and distance. galaxies in the universe regardless of their They are also wonderful experimental platform classification share the same core structure to test general relativity. Today millisecond called Active Galactic Nucleus (AGN). In the pulsars are one of the most accurate clocks center of these galaxies, a massive black hole that have been found in the Universe. RRI continuously drags intergalactic gas to its continues to conduct active research on depths and in the process forms around it a dough nut–shaped disk of matter called accretion disk. The matter in the disk may escape the black hole in the form of jets spreading in opposite directions. The velocity of these particles is relativistic allowing them to generate what is known as synchrotron radiation that reaches us and gets captured by our radio telescopes. Recently, there have been observations of radio galaxies with AGNs that are slowly dying out. How many such galaxies stay invisible to us because of the limitations posed by the sensitivity of today’s telescope receivers and what brings the end of

16 pulsars and develop receivers that would reveal further details about their nature.

Life cycle of Radio Galaxies - With the ever increasing sensitivity and resolution of today’s radio telescopes, intricate features and morphologies of and within radio galaxies can be observed. Peculiar type of galaxies called restarting radio galaxies have captured the interest of researchers at RRI. It is believed that declination range of -70deg to -10deg. The the activity in the nucleus of such galaxies had scientific objectives of MRT are to produce stopped for some time and then started again radio surveys of the southern sky, observe and fresh. Such a scenario would explain the study pulsars, solar radio emission, observations made and provide a useful input extragalactic radio sources, supernova to our understanding of the evolution and life remnants and steep spectrum sources. cycle of radio galaxies. Why did the nucleus Currently, a research group at RRI is analyzing die, how long it was dead before it restarted its data from a 150 MHz survey – one of the first activity, what are the mechanisms that extensive low radio frequency surveys of the triggered its rebirth – those are some of the southern sky. questions RRI astronomers are trying to answer in collaboration with Indian and international Giant Meterwave Radio Telescope (GMRT) – colleagues. GMRT is the largest low frequency telescope in the world used by astronomers from around Radio Galaxy Morphologies - In recent years, the globe. The collaboration between Tata the interest among the astronomy community Institute of Fundamental Research, Mumbai in what is known as X-shaped radio galaxies has (TIFR) which currently operates the telescope, grown and members of the A&A group at RRI and RRI has a long tradition. RRI has previously are active participants in this research field. In developed receivers in the 20-cm band as well X-shaped radio galaxies the typical two lobes as specialized receivers for pulsar observations are accompanied by two others to form a that have been installed on GMRT to improve radio galaxy whose lobes look like the letter X. its observational capabilities. Currently, Two of the lobes are active while the other two researchers and students at RRI are developing are dead. Theories compete to explain how the 50 MHz receivers for the GMRT. Such receivers two additional lobes are generated. Current have been installed on four of the GMRT observations at RRI are used to test these antennas. After extensive testing, a proposal theories and deepen our understanding of X- has been submitted for the fabrication and shaped radio galaxies. installation of the receivers on all 30 antennas

INSTRUMENTATION – DESIGN AND DEVELOPMENT

Mauritius Radio Telescope – Mauritius Radio Telescope was built in the late 90s in Bras d’Eau at the north-east side of Mauritius, in collaboration between RRI, Indian Institute of Astrophysics and University of Mauritius. It’s a T-shaped 2x1km aperture synthesis array which observed the sky at 151.6 MHz in the

17 to carry out an all sky survey at 50 MHz with unprecedented sensitivity and resolution in the low frequency regime. Low frequency surveys allow for statistical analysis of astronomical objects with high redshifts and also provide foreground information crucial for studies of the epoch of reionization (EoR).

Wideband Receivers on Green Bank Telescope – Researchers at RRI have developed a wideband multi channel receiver for pulsar observations that was recently installed in the largest single dish telescope in the world – the Green Bank Telescope in West Virginia, USA. The receivers sky. The MWA will consist of 8000 dual- allow for high time and spectral resolution of polarization dipole antennas optimized for the 80-300 MHz frequency range, arranged as 512 “tiles”, each a 4x4 array of dipoles. A test bed of 32 tiles is already deployed in the radio- quite zone in Western Australia, near the town of Geraldton providing the first sets of data from the instrument. RRI is a full partner in this project along with US and Australian institutions. Engineers and scientists from the A&A group have designed, built and tested the digital receivers and data processing electronics for the MWA telescope. Currently, they are looking at data collected with the 32- pulsar emissions. Data from the observations is tile test bed in an attempt to understand the currently being analyzed. efficacy of different observing, calibrating, and Decameter Wave Radio Telescope at data processing strategies for the detection of Gauribidanur – The decameter wave radio signals from EoR. telescope at Gauribidanur (80 km north of Ooty Radio Telescope – new broadband Bangalore) is built and operated by RRI and receivers that will allow for higher sensitivity Indian Institute of Astrophysics. It’s a 1.4 km and wider field of view are currently being (E-W wing) by 0.5 km (South wing) T-shaped designed and constructed at RRI for the Ooty array consisting of 1000 dipole antennas. Radio Telescope. Radio emissions from the Sun’s corona and various radio sources at 34.5MHz have been 15m preloaded parabolic dish – The institute is observed using the telescope. RRI researchers involved in the development of low-cost, are currently analyzing pulsar data collected robust 15m parabolic dish antennas that are using the E-W wing of the telescope. needed for grand telescope projects like Square Kilometer Array (SKA). The project is at Murchison Widefield Array (MWA) – MWA a stage when the mechanical aspects of the project is an international effort to design and design are being tested on a 12 m dish build novel low-frequency radio telescope to deployed at Gauribidanur. observe signals from the epoch of reionization, measure the heliospheric plasma and conduct 3m submm wave telescope prototype a high sensitivity survey of the dynamic radio (3mSTeP) – mm and submm wave bands are

18 extremely attractive for a number of reasons. experiment will be the pathfinder of future, Unlike optical radiation, mm and submm waves more sensitive experiments….Earth’s travel unabsorbed by the interstellar clouds atmosphere completely absorbs photons in and dust. This allows us to peak inside the the X-ray and gamma-ray band. Therefore, clouds where stars and galaxies are formed - a observations of X-ray sources can be carried main driving force in the development and out only from space platforms like balloons, construction of telescopes at these rockets, or satellites. To achieve a reasonable frequencies. Observations would also bring sensitivity, the proposed experiment requires valuable information about the cosmic very long observations of bright X-ray sources microwave background (CMB), the afterglow of that are only possible from a satellite.” the enigmatic gamma ray burst, star formation ASTROSAT LAXPC- ASTROSAT is the name given processes at high redshift, and more. However, to the Indian Space Research Organization the major problem at these frequencies is the (ISRO) satellite mission for multi-wavelength Earth’s atmosphere which is opaque for most astronomy, scheduled to be launched in a 650 of the band. That requires telescopes to be km near equatorial orbit in 2011. Its major deployed at high altitudes in order to minimize scientific goals include: (i) simultaneous multi- the travel of submm waves through the wavelength monitoring of intensity variations atmosphere. Members of the A&A group are in a broad range of cosmic sources; (ii) currently involved in the hardware broadband spectroscopic studies of X-ray development of a 3m submm wave telescope which would serve as a prototype for the development of a 30m telescope. They have already resolved challenges in the mechanical design of the dish and the development of an energy efficient motor system needed for the remote deployment, where power grid doesn’t reach. The group is currently working on the construction of very broadband 8GHz spectrometers needed for the telescope receiver system.

X-ray polarimeter – Recently, the A&A group has expanded its observations beyond radio and mm waves to the X-ray region of the spectrum. RRI has built a fully equipped lab for fabrication and testing of X-ray detectors and currently, researchers are working on the binaries, AGN, clusters of galaxies and stellar development of an X-ray polarimeter, sensitive coronae; (iii) sky surveys in the hard X-ray and in the energy range of 5-30 keV. The UV bands; (iv) studies of periodic and non- instrument will be launched in space in periodic variability of X-ray sources and more. collaboration with ISRO. The PI of the project ASTROSAT will carry five astronomy payloads says: “ The X-ray astronomical research and in a for simultaneous multi-band observations. RRI broader context, high-energy astrophysics is currently involved in the development of research will be strongly enriched from X-ray Large Area X-ray Proportional Counter (LAXPC) polarisation measurements of many kinds of for X-ray timing and low-resolution spectral astrophysical objects. In absence of any X-ray studies over a broad energy band. One of the polarisation mission presently approved payloads on ASTROSAT will consist of three of anywhere in the world, the proposed these identical LAXPCs.

19 ASTROPHYSICS

Dark matter halos play a key role in today’s models of galaxy formation and evolution. A dark matter halo is a hypothetical component of a galaxy extending beyond its visible boundaries whose existence is inferred by the effect it has on the motion of the gas and stars in the galaxy. As part of his research in cosmology and structure formation last year, Shiv Sethi studied supermassive black hole formation by direct collapse. He and his collaborators showed that the primordial gas in early dark matter halos, with virial temperatures just above 104K, could collapse directly to form a supermassive black hole (SMBH) if further cooling is avoided. Such a scenario is possible only in the presence of a sufficiently strong primordial magnetic field which heats the collapsing gas. A dependence of the evolution of the interstellar medium on the temperature and strength of the magnetic field was derived.

By observing mergers of compact objects, future gravity wave experiments like DECIGO, BBO and LISA would measure the luminosity distance to a large number of sources with a high precision, but the same doesn’t apply to their redshifts. Working with researchers from IISc and IUCAA, Sethi looked at ways to reduce systematic uncertainties in determining distance-redshift relation using self calibration techniques. The group provided an analytical expression for the achievable accuracy and derived a lower limit on the total number of sources that is needed to achieve this accuracy through self-calibration.

Shiv Sethi, Biman Nath (RRI) and Vasiliev (Southern Federal University, Russia), recently conducted a study of the far-UV background radiation spectrum with carbon lines in Lyman-alpha clouds at redshift z=3 which resulted in a paper being submitted to MNRAS in Dec 2009. The effect of He II absorption in the intergalactic medium at z=3 was studied using the available data of ionic ratios of carbon (namely CIII/CIV). Madau & Haardt ongoing research

20 predicted in 2009 that He II absorption would galaxies. Although a strong radiation field can lead to a significant change in this ratio with cause this deficiency, these observations respect to standard ratios calculated so far, become a puzzle when juxtaposed with the and this idea was tested with available data. largely observed abundances of other species, The statistical analysis suggests such as neutral magnesium, which can also be inhomogeneous abundance of He II at z=3, strongly affected by radiation. Nath teamed even extending down to z=2.5, indicating a up with researchers from Russia to investigate patchy He II reionization. the relative abundance of molecular hydrogen and Mg, first with analytical and semi-analytical Biman Nath’s research interests lie in the field approximations, and then with a full network of cosmology, structure formation and of reactions, in a variety of cases. During the extragalactic astronomy. A paper submitted to year, Nath has also worked closely with his MNRAS in Feb this year describes his work on colleague Sethi on various topics in the field of extended X-ray emission from radio galaxy cosmology and structure formation. cocoons. Nath developed a model in order to study the X-ray emission that has been S Sridhar’s interests lie in the theoretical observed in a number of FR-II type radio domain of galactic astrophysics. During the last galaxies. The model takes into account year, he worked extensively on the physics of injection of relativistic electrons, their energy the dynamo action due to turbulence in shear losses through adiabatic expansion, flows. It is well-known that helical turbulence synchrotron and inverse Compton emission, leads to the growth of large-scale magnetic and also the stopping of the jet after a certain fields (“dynamo action”). However, there are time. The evolution of the total X-ray power, astrophysical settings in which large-scale the surface brightness, angular size of the X- magnetic fields are seen in shear flows, but ray bright region and the X-ray photon index where the turbulence is expected to be non- were derived as functions of time and cocoon helical. Recent numerical experiments on such size. The model predictions were compared systems have reported dynamo action, but the with observations. The number of extended X- physics underlying such a “shear-dynamo” is ray sources above a certain flux level in a given not yet understood. Along with Kandaswamy portion of the sky was also estimated. Subramanian (IUCAA), Sridhar developed a formulation of the problem for a linear shear Gamma Ray Bursts (GRB), being the most flow. The analysis, results and conclusions can luminous electromagnetic events that occur in be found in a paper published in Physical our Universe, keep stirring the scientific Review E. Expanding on the same topic, curiosity of the astronomy & astrophysics Sridhar and his PhD student – Nishant Singh community. Recent observations of GRB show formulated the problem differently in order to a lack of molecular hydrogen in the host study dynamo actions under various scenarios. Their work is submitted for publication to the Journal of Fluid Dynamics and Physical Review E. Currently, Sridhar is collaborating with Kandaswamy Subramanian and Sanved Kolekar (IUCAA), addressing the dynamo problem in the context of the so called “renovating flows”. The real advantage of this approach is that it allows the investigation of the shear dynamo problem for arbitrary values of the magnetic Reynolds number and shear strength.

21 develop stellar-dynamical models for the nuclei of the Milky Way and M31. Using a very different approach to the problem, they were able to develop a largely analytical description of the evolution of the dynamical instability.

Rajendra BhandariBhandari, who retired recently, has worked for many years at RRI. His scientific curiosity kept him active until his last working day. During the last year, he has done Further understanding and a better theoretical theoretical work in the field of reflection description of magnetohydrodynamic (MHD) matrices, polarization transformations of light turbulence is another active area of research and non-modular topological phases. for Sridhar. The motivation behind his work is twofold: (i) to offer a review of the current Propagation of polarized light through an status of our understanding of incompressible optical system inevitably involves reflections MHD turbulence in a strongly magnetized from arbitrary surfaces resulting in plasma; (ii) to present a new result, pointing at transformation of the polarization state of a certain new length-scale that could arise in light. Such transformations are described by the imbalanced turbulence in the solar wind. 2x2 complex matrices which are fairly The approach taken is phenomenological even complicated functions of parameters of the where a more rigorous theory is available, so reflecting medium. Recently some constraints that a reader armed with paper, pencil and arising from the principle of reciprocity which some determination may be able to work must be satisfied by such matrices were through most of the physics. derived and their use as a tool to test derived expressions for such matrices was suggested. The nuclei of most normal galaxies are thought The tool was applied to several reflection to harbour supermassive black holes, matrices published in literature and in two surrounded by dense agglomeration of stars instances involving media with optical activity and gas. The stellar distribution can be the derived matrices were found to be in error significantly anisotropic, as evident from the thus establishing the usefulness of the tool. spectacular lopsided disc at the centre of the Andromeda Galaxy (M31). An idea Sridhar has Last year, Bhandari worked on an inverter for pursued over many years, suggests that these polarization transformation. Sandwich stellar systems could have originated through constructions consisting of a sequence of the development of a dynamical instability that transparent or absorbing polarization-changing affects stars belonging to successive merger elements for performing desired events. The instability is due to angular transformations on polarized light have been momentum transfer, facilitated by the long- important tools for a variety of applications in range gravitational interactions between the optics. It was shown recently that an SU(2) stars. Along with Tarun Deep Saini (IISc), he polarization element sandwiched between two presented a simple model that permits a orthogonal halfwave plates at 45o, produces a largely analytical exploration of the counter- transformation which is inverse of that rotating instability. Their work is in-press produced by the original element. This result in Monthly Notices of the Royal Astronomical was generalized to (i) pure dichroic elements Society. The same line of research is and (ii) elements which have dichroism as well manifested in the collaboration of Sridhar with as birefringence with the same polarization Jihad Touma (American University of Beirut, eigenstates. With electrically switchable Lebanon) where the goal is to ultimately halfwave plates this provides a simple way to

22 rotate a linear polarizer through 90o remotely spectral steepening towards lower frequencies, and at high speed without any moving parts. which is unusual. This low frequency spectral steepening is consistent with a combination of spectra from two populations of relativistic OBSERVATIONAL ASTRONOMY & electrons created at two epochs (two mergers) INSTRUMENTATION within the last ~ 0.5 gigayear. The low frequency observations are proving to be very K S Dwarakanath’s research activities important probes in understanding the throughout last year were guided by his long dynamics of clusters. lasting interest in extragalactic astronomy and clusters of galaxies. He and his PhD student Dwarakanath has also been collaborating with Ruta Kale presented a multi-wavelength astronomers Chandeyee Sengupta and D J analysis of the merging rich cluster of galaxies Saikia from NCRA in understanding an Abell 2256. The galaxy cluster A2256 was interacting system of galaxies. Observations of observed at 150 MHz using the Giant atomic hydrogen (HI) with the GMRT of the Metrewave Radio Telescope (GMRT) and a interacting galaxies NGC5996 and NGC5994, diffuse radio emission over an extent of about which make up the ARP72 system were carried a million light year was detected. Using this out. Arp72 shows a complex distribution of HI 150 MHz image and the images from the tails and bridges due to tidal interactions. The archival observations from the Very Large Array regions of high HI column density in the bridge (VLA) at 1369 MHz and the Westerbork of emission connecting the two galaxies, which Synthesis Radio Telescope (WSRT) at 330 MHz, is also seen at optical, infrared and ultraviolet images of the ratio of the intensities (spectral wavelengths is in the range of 1.7-2X1021 index) of the diffuse radio emission at atoms cm-2. An eastern tidal tail with HI different frequencies were produced. The column densities in the range of 0.8-1.8X1021 spectral index values of the diffuse emission atoms cm-2 is seen prominently in the GALEX show variations across the cluster. These satellite image at ultraviolet wavelengths spectral indices indicate synchrotron life times indicating regions of massive star formation. for the relativistic plasmas from a merger Further studies involving kinematics of ionized event within the last 0.5 gigayear or so. The and molecular gases with a view to obtain a diffuse emission is generated by the more comprehensive picture of this interacting turbulence injected by such a merger event. system is in progress. Furthermore, the diffuse radio emission shows Radio galaxies triggered a long-lasting interest in Lakshmi Saripalli and have been a primary focus in her research career. Radio galaxies manifest in several different extended radio structures. The most typical is the twin lobe structure, but some radio galaxies exhibit a variety of lobe morphologies (double-double, X-shapes and giant-lobe radio galaxies). The origin of these lobe morphologies is not well understood. Major part of

23 Saripalli’s work this year was prompted by the Sydney). It presents a radio survey carried out discovery of the unusual radio galaxy B2014- with the Australia Telescope Compact Array 558, whose observed X-shaped structure could (ATCA). The survey was prompted by the need not be explained by the existing set of models. to make a complete inventory of the diffuse The relationships between the radio emission components as a step towards a morphology in double radio sources and the study of the cosmic evolution in radio source radio-optical position angle offset (the relative structure. The Australia Telescope Low- orientation of the radio axis with respect to the Brightness Survey (ATLBS) at 1388 MHz covered major axis of the host galaxy) were examined 8.42o2 of the sky in an observing mode for a representative sample of radio sources designed to yield images with exceptional (the nearby 3CRR sources), and separately for surface brightness sensitivity and low samples of giant radio sources and X-shaped confusion. The observations provided a radio sources. The observations of the measurement of the complexity and diffuse dependence of radio morphological features emission associated with mJy and sub-mJy on the radio-optical position angle offset, and radio sources. on whether the radio-source axis is closer to The areas of scientific exploration for N the host major or minor axis, were published in Udayashankar include sky surveys as well as the Astrophysical Journal, with Ravi instrumentation and signal processing for radio Subrahmanyan as a co-author. astronomy. Last year, his research activities A paper titled “ATLBS: the Australia Telescope continued in the same direction. An all sky Low-Brightness Survey” was published this year survey at 150 MHz using the Mauritius Radio as a result of the collaboration between Ravi Telescope (MRT) is under way where the survey Subrahmanyan, Lakshmi Saripalli, Ron Ekers is expected to image approximately 4.8 sr (CSIRO ATNF) and Elaine Sadler (University of (steradians) of the southern sky. This survey is an expansion of a previous one which covered approximately 1.2 sr. Work related to imaging and source extraction for the remaining 3.6 sr of the sky has been carried out by Sootash Daiboo and Arvind Nayak. The array geometry was re-established, new calibration tables, and new point-source functions (PSFs) for deconvolution were generated. To improve the calibration technique, a field of view calibration scheme was developed, which uses MRT images of the sky one sidereal hour prior to the data selected for imaging. With these new developments imaging of an additional steradian of the sky was completed with an average noise reduction of about 20%.

Four low frequency receiver systems were developed in RRI and installed on four of the GMRT antennas. Based on their satisfactory performance, a proposal was submitted seeking guaranteed time of around 600 hours for an all sky survey at 50 MHz. Collaborators of Udayashankar on this project are Dwarakanath (RRI), S.K. Sirothia (NCRA) and Y.

24 Gupta (NCRA). On approval of this proposal, thirty receivers and feeds required for this survey will be built. The commissioning (expected to take about a year) and the survey will be carried out jointly by the National Center for Radio Astrophysics (NCRA) and RRI. The expected sensitivity is an order of magnitude better than that of the best low- frequency survey available to date (the VLA Low-Frequency Sky Survey at 74 MHz). It is also comparable to the sensitivity of the 1.4 GHz VLA Sky survey (NVSS) done by the National Radio Astronomy Observatory, USA. Furthermore, this survey is expected to be sensitive to low surface brightness and extended features that are likely missing in other surveys. A variety of studies involving sources in the Galactic plane, diffuse extended extragalactic sources, spectra of extragalactic sources and source counts are expected to be carried out with this survey data. The final products of the survey (images and source catalogues) will be made available on the working on the assessment of drift-scan World Wide Web within 12 months from the strategy for the detection of Epoch of Re- date of completion of the last successful ionization (EoR) signal. RRI team has carried survey observations. out observations of three regions of the sky using the MWA 32-tile system to compare the Teamed up with the Mechanical Engineering expected and the measured sensitivities in group at RRI, Udayashankar is working on the tracking and drift scan modes. Data analysis is development of 15m parabolic dish antennas. under progress. Preliminary design studies showed conclusively that there was no specific advantage in Currently, Avinash Deshpande is working with preloading a dish with regard to obtaining a a group of astronomers from the USA and lesser weight-per-unit-area. A detailed design Mexico in an attempt to better understand study of a 15-m Bent Spoke Dish, which uses and analyze OH masers. Masers are a type of plastic bent spokes for the backup structure astrophysical sources of stimulated spectral was completed and documented in a technical line emission, typically found in the microwave report. Examination of the feasibility of using portion of the electromagnetic spectrum. electromagnetically transparent fiberglass W49N is one of the most luminous regions of structural members for the quadripod, and active star formation in the Galaxy. A 12-hour adding a third axis of rotation to minimize the synthesis OH-line data from the Very Large problems of polarization calibration is under Baseline Array (VLBA) telescope, in the discussion with a consultant. directions of W49N and W3OH, were obtained and are currently being analyzed. The detailed RRI is a collaborator in the international high angular-resolution images at 1612, 1665 Murchison Wide Field Array (MWA) project. and 1667 MHz reveal scattered broadened OH Udayashankar, Deshpande, Subrahmanyan and spots, indicating anisotropic scattering, with Vedantham, who joined recently, have been the position angles of the spot images

25 oriented perpendicular to the galactic plane. shipped to Green Bank. It was installed and This is interpreted in terms of scattering due to interfaced with the GBT fiber-link, and the first electron-density irregularities being oriented light observations was successfully made on parallel to the galactic plane due to influence 1st June 2009. Pulsar observations were made of similarly aligned local magnetic field. Further during July and August and the detailed investigations are in progress. analysis of these data are in progress.

Deshpande is a part of a large team of Harish Vedantham recently joined the Institute researchers, engineers and students from RRI and have since been actively involved in the and Green Bank Telescope at the National MWA project. MWA belongs to a new Radio Astronomy Observatory (NRAO), USA, generation of low frequency interferometric who have developed a multi-band receiver radio telescopes and it’s currently being (MBR) for pulsar observations. The MBR system commissioned in the interference free Western will enable tomographic study of pulsar Australian desert. Working with Ravi emission. The receiver system was designed Subrahmanyan and Udayashankar, Harish is and built at RRI, and is now mounted on the trying to process MWA data to understand the Green Bank 110-meter telescope. It consists of merits and demerits of different observing, a multi-band feed with 10 spectral bands from calibrating, and data processing strategies. This 100 to 1600 MHz, an RF front-end, and ten will eventually lead to estimating the statistics computer-controlled receivers, each catering of spatial 3-dimensional fluctuations in the to one band. The receivers consist of a high- 21cm signature from the Epoch of gain heterodyne receiver chain, digitizers, and Reionization. Such studies will bridge a gap in an FPGA-based back-end, enabling raw-voltage our understanding of the early evolution of recording of dual-polarization data with 16 the universe and consequently constrain/ MHz bandwidth. The design of suitable dual- improve current cosmological models. polarization feed for multi-band operation was Research interests and endeavors of the done. A feed-testing facility was developed at institute members stretch to the sub- RRI’s field station in Gauribidanur, and millimeter portion of the electromagnetic spectrum analyzer based procedures for spectrum. B Ramesh has proposed a new measuring antenna parameters were optics design that allows for building large sub- developed. After suitable software and millimeter telescopes very economically. The hardware upgrades were incorporated and construction of a 3m Submillimeterwave tested at Gauribidanur, the MBR system was Telescope Prototype (3mSTeP) based on such

26 were carried out to improve the efficiency of the system. At present, resistive wires in the X- ray detectors allow for position determination and spectral measurements. Much attention was paid to the development of efficient processing electronics system. An FPGA based coincidence and anti-coincidence logic system, and simultaneous charge measurement system have been developed and tested successfully. As a result, the processing electronics unit of the polarimeter was reduced and the processing power increased. Simulations for design optimization and preliminary tests of design is under way. The mechanical structure the cylindrical proportional counter detector design and optimization were completed last for a Thompson X-ray polarimeter were also year. Work on the 8 GHz wideband carried out during the year. Major spectrometer for the 3m STeP is now contributions to this work come from the underway. Given that velocity range covered engineers in the X-Ray Astronomy Lab at RRI. by a spectrometer is proportional to its Paul serves as LAXPC representative in the fractional bandwidth, sub-millimeter wave ASTROSAT Ground Segment Committee that observations require wideband, coarse takes care of all ASTROSAT activities other than resolution spectrometers. A detailed design of the hardware development. Working closely the IF processor and the sampler-DSP board with two teams at ISAC, Bangalore and SAC, was undertaken to ensure useful, timely and Ahmedabad, he designed the data reduction economical realization of the spectrometer. By pipe-line for LAXPC and is currently working efficiently choosing the local oscillator towards preparation of the data formats of frequencies and using direct digitization, the the ASTROSAT-LAXPC, both at the intermediate processor has been designed to minimize the and user distribution level. number of local oscillators and filters required. The driving system for the 3m STeP is yet In the area of observational astronomy, the another challenge. A new circuit design with scientific research of Paul includes pulsars, higher power efficiency, and reduced number active galactic Nuclei (AGN) and transients. of component compared to the commercial Working alongside scientists from Physical PWM drive systems was designed, implemented and tested to work at the required 20V output voltage. A stand-alone unit with special purpose PCB made for this application was also built.

Biswajit Paul and his students at the Astronomy and Astrophysics Group stepped in the yet unexplored area of X-ray polarization measurements. Such measurements will largely enhance our understanding of several important high energy astrophysical problems. Large amount of time and effort were spent in the last year on the development of an X-ray polarimeter. Modifications of the initial design

27 Research Lab (PRL), Ahmedabad and Delhi low-surface-brightness (LSB) galaxy UGC 6614. University, Paul analyzed the recent step like The X-ray properties and spectra of the central flux enhancement in the X-ray pulsar 4U 1626- objects in LSB galaxies are yet to be actively 67. The analysis of the data from the explored. XMM-Newton archival data was used Proportional Counter Array (PCA) instrument to study the characteristics of the X-ray carried on Rossi X-ray Timing Explorer (RXTE) spectrum and flux variability of the active showed that the persistent MHz quasi-periodic galactic nuclei (AGN) of UGC 6614. The results oscillations in this source disappeared after the of this study demonstrated that, although LSB flux change, and the X-ray spectrum galaxies are poor in star formation, they may considerably changed. harbour AGNs with X-ray properties comparable to those seen in more luminous Another study of the binary pulsar KS spiral galaxies. 1947+300 was done using data from the same instrument and quasi periodic oscillations Paul’s research last year also included data (QPO) at 0.02 Hz were discovered. Paul and his processing and analysis of data from three collaborators argue that the detection of QPOs different instruments (Swift-BAT, RXTE-ASM and and strong pulsations at a low luminosity level Integral-IBIS) to carry out a detailed orbital suggest that the magnetic field strength of the modulation study of three high mass X-ray neutron star is not as high as was predicted binaries (HMXB). earlier.

Paul was also a collaborator in the study of the X-ray emission from the nuclear region of the

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LightLight ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ andand MatterMatter PhysicsPhysics

29 The Light and Matter Physics (LAMP) group consists of four highly motivated faculty members and their students that started in 1995. Interactions between light and matter are ubiquitous in the Universe! Understanding the patterns and mechanisms of these interactions, and their governing laws reveals many secrets about the nature of both light and matter individually. Solid fundamental understanding of such interactions opens up to an enormous field of potential applications, ranging from detection of gravitational waves to laser based medical imaging. The members of LAMP group combine knowledge from atomic, molecular, linear and nonlinear optical physics to study classical and quantum light – matter interactions. One unique feature of the group is its holistic scientific approach, where theoretical, numerical and experimental research complement each other. There are three labs for laser cooling and trapping catering to the individual needs of the LAMP members. A laboratory is set up to study light propagation in random media, and experiments are conducted regularly in both the nonlinear optics lab, and laser- induced plasma lab.

The following pages summarize the major areas of research for the LAMP group. Each member’s individual work during the last year is provided in the next section, giving the reader more detailed and technical description of their respective research activities. overview

30 QUANTUM OPTICS of the chamber, and increases radially outward. Using appropriate wavelength Quantum optics is a field in physics that applies and polarization of the laser beams, quantum mechanics to study light phenomena atoms can be cooled by repeated and light-matter interactions. Since the first absorption and emission of light, and indication that light may be quantized in 1899, trapped by an inward force arising out of the field of quantum optics has witnessed the combination of the polarised light significant progress in our understanding of beams and the spatially varying magnetic light-matter interactions and microscopic field. Such a system is called Magneto systems. Today’s major fields of interest in Optical Trap or simply, MOT. quantum optics include manipulation of elemental particles like atoms, ions and 2D MOT – Researchers from the LAMP molecules, and the use of quantum optics for group are continuing their work on the quantum information. The LAMP group has construction of a 2 dimensional MOT. adopted a basic science research approach, as Currently, they are involved in the process opposed to a competitive technology of installing and testing the coils that development approach, in keeping with the produce the magnetic force in the MOT. overall philosophy of the Institute. MOT and Quantum Logic - Quantum logic is LASER COOLING AND TRAPPING an attractive area of research for the LAMP group. With the ever shrinking electronic Laser cooling and trapping is an area of devices, quantum effects like superposition physics that has largely expanded over the and entanglement cannot be ignored and last decade. Presently, atoms can be new ways of defining the basic states of 0 cooled down to extremely low kinetic and 1 should be investigated. To achieve temperatures (as low as 1 K) and trapped µ quantum logical gates, the atoms need to for a time period on the order of seconds. be cooled and trapped in optical lattices, Such control over the motion of atoms such that the 0 and 1 states of a digital allows researchers to probe their behavior circuit can be mapped to internal states of more precisely than ever before. There are the atom. The inducing of conditional a number of techniques to cool and trap transitions between these states is the atoms of alkali elements and the most equivalent of a logical gate. Currently, a commonly used is called Doppler cooling. It MOT with the capability of trapping involves three mutually perpendicular laser individual atoms is being built at RRI. beams that intersect at the centre of the chamber. A pair of magnetic coils produce A Lattice of Ion Traps – Researchers at RRI a magnetic field that is zero at the centre have proposed a novel ion trap configuration which allows for high precision spectroscopy measurements, quantum information processing as well as new studies of few-particle interaction systems.

Ion-Atom System – Attempting the synthesis of ultra cold molecules from ultra cold atoms (with the emphasis on dipolar molecules), LAMP members have constructed and fully characterized the necessary experimental system that is

31 capable of trapping both atoms and ions within the same region of space.

A novel technology for laser cooling and trapping – the LAMP group at RRI is also engaged in the construction of a system capable of trapping atoms, ions, molecules and photons. Such a system will create opportunity to study quantum mechanical effects in cold atoms/ions/molecules and expand our knowledge of ultra-cold the fields of computer science, physics, molecular physics. ecology, economics and psychology. ELECTROMAGNETICALLY INDUCED Quantum walks are the equivalent of TRANSPARENCY (EIT) random walks in quantum computing and can form a part of a quantum algorithm. EIT is a quantum mechanical phenomenon, LAMP group members are now where under specific conditions, an investigating quantum walks of light in absorption line of a material can be frequency space. cancelled, changing it from opaque to transparent at that particular frequency. To observe EIT two highly coherent lasers are LIGHT PROPAGATION IN tuned to interact with three or more RANDOM MEDIA quantum states of the material. Since 1990 considerable research activity has been Multiple scattering of light in random media, devoted to the topic of EIT. RRI researchers like fog, considerably reduces visibility. are trying to build a strong fundamental Researchers at RRI have developed a technique understanding of the EIT phenomenon, for imaging in turbid media, which is currently using both theoretical and experimental being tested for commercial applications like methods. aircraft navigation.

QUANTUM WALK OF LIGHT The localization of light in random media is a phenomenon, which is not well understood. A random walk is a mathematical After extensive simulations, members of the description of a trajectory, where the LAMP group are now attempting to successive steps are random. Classical experimentally observe localization of light, random walks are used in search using ferrofluids as a medium. Ferrofluids algorithms when the searched parameter consist of a fluid (usually water) with space is random. They find application in ferromagnetic nanoparticles, that act like random scatterers, when dispersed in it. The easy manipulation of nanoparticles in ferrofluids, allows to test quickly various possible scenarios that lead to localization of light. The understanding of this phenomenon can open doors for future novel optical devices.

32 Naturally, such plasmas are called laser induced plasmas and they find application in many technological fields. In material science, Pulsed Laser Deposition is the most commonly used technique for thin film production. Optical emission spectroscopy of a laser induced plasma, called Laser Induced Breakdown Spectroscopy (LIBS), is a powerful technique that provides immediate elemental analysis of any matter, regardless of its physical state. LIBS is widely used for the detection of heavy metals in soil, aerosol characterization, cultural heritage elemental analysis, process control in NONLINEAR OPTICS industry, space exploration, etc. Laser induced When a material is probed with a very high plasmas are also used in the field of medical intensity optical field, responses like reflection, diagnosis and surgery, laser ignition, propulsion transmission and absorption no longer scale and fusion. Researchers from the LAMP group linearly with the intensity of the applied field. conduct a large number of experiments to Nonlinear optics is a branch of optics that study the time evolution and spectral studies such nonlinear effects in various characteristics of laser induced plasmas. The materials. It forms a broad field of research, targets used can be solid or liquid samples and with device applications in the experiments are performed in vacuum as telecommunications, optical storage and all well as in ambient pressure condition. optical computing. Optical switches, saturable absorbers and optical limiters are just few examples of devices based on the principle of nonlinear transmission. The LAMP group at RRI investigates the nonlinear optical properties of various types of materials, with an emphasis on nanoparticles and nanocomposites. To study the temporal behavior of nonlinearities, the group uses femtosecond pump-probe spectroscopy. Other frequently used experimental techniques used pulsed laser z- scan, degenerate four wave mixing (DFWM) and white light z-scan.

LASER INDUCED PLASMA

Lightning is a beautiful (and often dangerous) example of how Nature can create plasma. Today, the technological evolution of lasers allows researchers to routinely generate plasma in their labs, using very high power pulsed lasers.

33 QUANTUM AND CLASSICAL OPTICS

The 3GHz magnetic dipole transition between ground hyperfine levels of Rubidium 85 is famous for the clock resonance in Rubidium clocks. Andal Narayanan’s group at RRI fabricated a 3 GHz microwave cavity in order to study the possibility of coherent transfer link, namely microwaves-optical waves-matter link, during an electromagnetically induced transparency (EIT) phenomenon. First, the coherence of the microwave field gets transferred to the optical domain and then using EIT it is transferred again quantum mechanically to the matter. This is possible because EIT is a quantum mechanical effect which preserves coherence. Last year, Narayanan was engaged with the full characterization of the custom build 3 GHz microwave cavity. The quality factor Q of the cavity was measured to be as high as 4000. At the center frequency, the required special mode was successfully coupled with high efficiency and good signal to noise ratio. Testing of the temporal range of efficient cavity coupling is under way.

Narayanan and the visiting researcher M. Manukumar from Bangalore University have found an experimental signature that uniquely identifies interacting superposition states of internal levels of Rubidium. The experiments with Rubidium atoms were done at room temperature in a vapour cell. The observed signature is qualitatively similar to the fringe pattern in a Young’s double slit experiment. The “visibility” of the fringe pattern helps to identify spectral positions of interacting states of equal strength. It’s envisioned that this result will eventually hold for true quantum superposed states of light and matter.

Simulations of microwave based quantum optical experiments are another active area of research for Narayanan. A density matrix numerical calculation was carried out for various coupling schemes of Rb 85, addressing the question of the relative phase coherence ongoing research

34 replacing the conventional beam splitter by a polarizing beam splitter and (ii) shifting the frequency of light in one path up by a certain amount and down by the same amount in the other path. A cascade of such modified interferometers was arranged, and the final interference pattern was the manifestation of a quantum walk.

Hema Ramachandran’s work towards quantum logic with cold atoms, involved the setting up of a magneto optical trap (MOT) with the of phase sensitive signals, involving both ability of trapping individual atoms within the microwave and optical light fields. The MOT. Trapping of individual atoms can be possibility of squeezing the quadrature noise achieved using a very tightly focused laser below the quantum limit is currently being beam that forms a steep dipole trap. It was investigated. A novel EIT scheme involving two found that for the size and position of the lens photon optical resonance and a microwave that produces the required focused light the field is studied. The next step is to use these MOT beams must be inclined at about 60º, calculations to experimentally test these results rather than the usual 90º. This made the beam in the laboratory. alignment and intensity matching quite The successful microwave and room challenging. Success was reported in trapping temperature experiments have been the multiple atoms with beams inclined at such primary, but not only focus of Narayanan’s angles. research last year. The building of coils for a Multiple scattering of light in a random media two dimensional magneto optical trap (MOT) like fog, or muddy water, considerably reduces has started recently. This new setup will visibility. Ramachandran, Mehdi Alouini increase the total number of atoms available in (University of Rennes) and Fabien Bretenaker the trap – a condition required for the (Univeristy of Paris) have developed a envisioned future cold atom experiments in technique for imaging in turbid media that quantum optics. offers simplicity of implementation. An Quantum computing is one of the major experiment was designed to find out whether research interests of Hema Ramachandranamachandran. this technique could be utilized for navigation She has conducted both theoretical and experimental work in the field of quantum walks. The theoretical investigation of a one dimensional Hadamard walk by cold atoms in a double optical lattice, has now been published. This work discusses the parameters under which present day experimental capabilities permit observation of this phenomenon. Last year, her team studied the quantum walk of light in a simple tabletop experiment using the analogy with the classical interference experiment. For demonstrating the quantum walk of a photon in frequency space, a Michelson interferometer was modified by (i)

35 of aircraft under reduced visibility. A polarized QUANTUM INTERACTIONS light source is to be placed on top of a high Sadiq Rangwala’s group conducts scientific tower (TV tower in Rennes, France), and and experimental research in the field of polarization based imaging optics in a quantum interactions. In their paper titled laboratory 2 kilometers away. The intention is “Three-dimensional Lattice of Ion Traps”, they to study the feasibility of imaging under propose and numerically characterize an ion various extents of visibility. The early morning trap which is three dimensionally symmetric. fog which is present at Rennes for nearly six Individual traps can in addition be stacked in a months of the year makes it ideal for such tight packed arrangement. Such a experiments. configuration will open the door to a fresh set In an effort to understand the puzzling of possibilities for future experiments with absence of transmission and apparent storage highly symmetric and multiple ion traps. Such of light reported in a medium comprising a system could be of great value, as the limited nanometric and micrometric magnetic numbers of ions available to work with spheres, Ramachandran has taken up a represents a serious constraint for several systematic study of the light transmission experiments. It is numerically demonstrated properties in a ferrofluid as a function of field that neighboring traps have little effect on and the polarization state of light. It was found each other for the purposes of several that as light transmission decreases, it is potential applications. Specifically the actually scattered sideways, or normal to its relevance of this trap to “ion clocks”, initial direction of propagation. The role of the “quantum information processing” and “few- larger magnetic particles is now being particle interacting systems” are discussed in investigated. their paper. Extensions of this concept to many applications in fundamental and applied As part of her research on novel optical physics and for applications requiring lower applications of nanomaterials, during a recent symmetry are also possible, as suggested by collaboration with Deepak Mathur (TIFR) on Rangwala’s group. light emission by carbon nanotubes (CNTs), Ramachandran observed the formation of A major project of the group was the building bubbles in the surrounding fluid. These and full characterization of the ion-atom bubbles could be trapped at the tweezer experimental system. The experimental focus. Their formation was attributed to the observations and results include: (i) the photo-thermal heating of the CNTs and its successful and simultaneous trapping of cold vicinity, leading to the expulsion of hot gas atoms 85Rb and ions 85Rb+ ; (ii) successful from within the CNTs and vaporization of the detection of the effect of trapping the ions in immediate surrounding fluid. CNTs, which are usually repelled by the tweezer focus due to the dipole force, were now found attracted towards the bubbles; they adhered to the bubble surface and could thus be micromanipulated. This suggested the possible use of the microbubbles as scavengers of CNTs. The effect was demonstrated in static condition as well as fluid flow, both in the direction of flow and against it.

36 the presence of cold atoms on both- the ion and photons. Major science objectives are and the atom signals; (iii) reliable estimation of Ca+ ion trapping, molecule synthesis by the number of atoms and ions; (iv) successful photo-association, trapping of 39K or 40K in measurement of the temperature of the ions the cavity (MOT), using cold Rb atoms to in the trap. The detection technique for the perform the switching experiments and more. ions, though unusual for this class of The system was constructed and tested in the experiment, is robust and reliable. Future plans period of June-November last year. The most include the synthesis of ultra cold molecules sensitive part, the Fabry-Perot cavity inside the from the ion-atom mix, measurement of the vacuum system, performed significantly better ion-atom collision cross-sections, mixed than expected. Currently, a small slackness in species ion atom experiments, as well as the the ion trap structure prevents experimental highly challenging optical, non resonant, work in vacuum. The redesigned version of the detection of trapped ions. system is expected to start soon.

Sadiq Rangwala’s cold molecules project Sadiq Ranqwala is part of an international requires extremely low light level detection. effort towards a more detailed investigation of The most sensitive detection technique today anti-relaxation coatings for alkali-metal vapor is resonant detection via cavities. Before cells using surface science techniques. Many attempting cold molecule detection, the technologies based on cells containing alkali- technique must be tested on hot and then metal atomic vapor benefit from the use of cold atoms. Two experiments with Rb 87 were anti-relaxation surface coatings in order to performed where the transmission properties preserve atomic spin polarization. In particular, of a cavity containing atoms were studied. paraffin has been used for this purpose for Several interesting features in the laser-atom- several decades and has been demonstrated cavity system have been explored. to allow an atom to experience up to 10,000 Interestingly, it was found that transmission of collisions with the walls of its container without the resonant light into the cavity mode can be depolarizing. Modern surface and bulk completely switched OFF and ON by techniques were applied to study paraffin addressing the atoms in the cavity with a side coatings, in order to characterize the laser. For negative or positive logic switching, properties that enable the effective the two laser beams (cavity mode and side preservation of alkali spin polarization. These laser) must resonantly connect the excited methods include Fourier transform infrared state manifold to two distinct or equal ground spectroscopy, differential scanning calorimetry, states, respectively. No specific alignment is atomic force microscopy, near-edge X-ray required for the side beam, just that it absorption fine structure spectroscopy, and X- intersects the cavity mode at one spot. After ray photoelectron spectroscopy. the experiment, the theoretical model that explains the qualitative features of the switching has been constructed. Future LASER INDUCED PLASMA AND envisioned experiments include positive and NONLINEAR OPTICS negative logic switching with atoms in paraffin Laser induced plasma is one area of expertise coated cells and switching experiments with for Reji PhilipPhilip. This year his research was potassium. This project is done in collaboration focused on spectroscopic studies of laser with researchers from University of California induced plasma. The ultrafast laser-induced at Berkeley. plasma was generated from solid (Nickel) or For the past several years Sadiq Ranqwala’s thin film targets. In the case of solid targets, group is also working on a system capable of the X-Ray and gamma ray emissions were trapping cold atoms, cold molecules, cold ions observed, while for thin film targets Philip

37 Conventionally, a tunable laser is needed to measure the wavelength dependence of optical parameters with spectral dispersion. However in some cases, a white light continuum may be a suitable substitute for the tunable laser. The white light continuum is an intense broadband emission obtained from media like photonic crystal fibers, when they looked at the visible emissions. A hundred are excited using an ultrafast laser. It has a femtosecond laser pulses of 10 mJ energy large spectral extent ranging from the UV to IR from a Ti:Sapphire laser were focused using a region with high intensities and short time 60 cm plano-convex lens at the target, which scales. If white light continuum is used as the was kept in vacuum. The target was moved source, the dispersion of optical nonlinearities between successive laser shots using a target over a range of wavelengths can be measured manipulator so that the plasma was generated in a single z-scan experiment. Philip’s group from a fresh surface every time. The resulting has set up the white light z-scan experiment peak intensity was about 1015 W/cm2. A and a few measurements have been done. It calibrated detector was used to collect the was found that the intensity of the continuum spectra, and the hot electron temperature was was spread over a large wavelength range, calculated from the Bremsstrahlung emission leading to lower S/N ratios. Improvement of spectrum. The electronics and software the set up is now under way. required for the target manipulator were developed in-house. The equipment needed Sunita Sharma joined the LAMP group as a for spectroscopic investigations of plasma post-doc focusing her research on produced from thin film samples was nanomaterials, solar cells, biosensors and completed in collaboration with the Institute of nonlinear optics. Exploring the vast potential Plasma Research. An additional vacuum for applications of nanomaterials in solar cells chamber was attached to the existing and optoelectronic devices, Sunita works on chamber. Using a three-wire Langmuir probe, reducing wafer thickness, and improving the ion and electron current measurements from quantum efficiency of solar cells. the thin film plasma were carried out. The In line with her research on biosensors, Sunita preliminary measurements showed that the conducted morphological (X-Ray Diffraction plasma was not consistent. Currently, ways of and Differential Scanning Calorimetric) and improving the plasma consistency are being optical (Fourier Transform Infrared and UV-Vis investigated. absorption) studies of silica matrices with Philip actively studies the nonlinear optical entrapped Rhizobial (Rz) structure. Her properties of nanomaterials and other media. collaborator was Mr. Sandeep Menon from Collaborating with experts, who synthesized Macquarie University Sydney, Australia. Sol-gel the various materials required for this study, derived silica has tremendous applications as a Philip investigated the optical nonlinearity of biocompatible scaffold for the immobilization different types of media, using the open of cells. The use of xerogel as a matrix in the aperture z-scan experiment. These include blueprint of biosensors is an appealing organics, inorganics, semiconductor quantum proposition due to several inimitable dots, metal nanoparticles, and characteristics of xerogels like their high nanocomposites. Some of these materials porous nature, amendable pore size, and were found to be potential candidates for exceptionally large internal surface area. optical limiting and photonic device applications.

38

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39 The Soft Condensed Matter (SCM) group was for a long time called Liquid Crystals group with its research activities concentrated in the area of liquid crystal synthesis, characterization and other analysis of their physical properties. During the forty years of its existence the group has made important contributions to the field of liquid crystals. Keeping the focus on fundamental research, the group has recently expanded its activities to investigate other soft condensed matter like polymers, colloids, amphiphilic systems and nanocomposites. Theoretical and experimental research today includes the well established area of liquid crystal synthesis and characterization as well as electrochemistry and surface science, liquid crystal displays, rheology studies of soft condensed matter and biophysics. The research environment in the SCM group is highly interactive with constant knowledge sharing and exchange of ideas among chemists, electrochemists, condensed matter physicists, theoretical physicists and members with statistical physics expertise.

The following pages summarize the major areas of research for the SCM group. Each member’s individual work during the last year is provided in the next section, giving the reader more detailed and technical description of their respective research activities. overview

40 LIQUID CRYSTAL SYNTHESIS

A liquid crystal is a liquid whose atoms or molecules are regularly arranged in one or two dimensions such that it exhibits some optical properties associated with crystals. Liquid crystals exist in the so called mesomorphic state, or a state of matter between liquid and solid. A mesogen is the fundamental unit of a liquid crystal (LC) that is responsible for the structural order observed in these substances. Typically, liquid crystal molecules consist of a rigid and flexible part. The first one gives rise to the crystalline properties in a liquid crystal, while the second causes the fluidity. The molecules of liquid crystals are usually referred to as mesogens. There are several varieties of liquid crystals. Few of the important classifications are based on the shape of the molecules, orientation of the molecules, and nature of the material. Smectic LCs have molecules that are aligned in a series of layers, with the axes of the molecules perpendicular to the plane of the layers. Nematic LCs have their molecules arranged in loose parallel lines. Calamitic LCs have the so called rod-like mesogens while discotic LCs have disc-like some of them exhibiting novel mesophases mesogens. There are also a class of LCs (the phase between crystalline and isotropic synthesized with bent-core or banana shaped liquid) and interesting properties like mesogens. Thermotropic LCs exhibit phase spontaneous electrical polarization. The lab is transition into LC as temperature changes, equally active in the synthesis of novel disc-like while lyotropic LCs phase transition is a mesogens that have important electronic and function of both temperature and mesogen optoelectronic properties. Collaborating with concentration in a solvent. other members of the SCM group, the Chemistry Lab often synthesizes compounds LCs are primarily known for their extensive that exhibit specific physical properties like exploitation in electro-optical display devices ferroelectric, antiferroelectric or columnar such as watches, calculators, telephones, phase. Oligomeric and polymer mesogens and personal organizers, laptop computers, flat compounds with novel metallo-mesogens with panel television, etc. They also have diverse magnetic properties are also investigated. The applications in chromatography, spectroscopy, lab is equipped with polarizing microscope, holography, temperature sensing, as solvents differential scanning calorimeter, digital in chemical reactions and more. micropolarimeter, infrared spectrophotometer, The Chemistry Lab at RRI is involved in the UV-vis spectroscopy, in addition to basic synthesis and characterization of a wide range equipments required for chemical synthesis. of liquid crystals. More than 700 compounds with bent-core or banana-shaped molecules have been synthesized and characterized, with

41 PHYSICAL MEASUREMENTS LIQUID CRYSTAL DISPLAYS (LCDs) Members of the SCM group at RRI investigate phase transitions, structure, molecular LCD technology is the most common and wide organization and physical properties of spread display technology in the world today. thermotropic liquid crystals with rod-like, disc- LCDs are literally everywhere: in our cell like and bent-core banana shaped molecules. phones, televisions, laptop computers, video The magnetic properties of liquid crystals and players, digital watches, calculators, gaming their nanocomposites are also currently being devices! They are much thinner, lighter, studied. Nanocomposites (nanoparticles – portable, less expansive, more reliable and liquid crystal composites) are another active draw much less power compared to the old area of research. Dispersion of metallic, cathode ray tubes. Research activities at RRI magnetic or ferroelectric nanoparticles in focus on the development of new addressing different liquid crystals is very promising for techniques for drive electronics in LCDs with novel future device applications. One of the passive matrix, that would further reduce major challenge in the field is the power dissipation and hardware complexity. understanding of the mechanisms of self RRI has patents related to its research activities assembly of nanoparticles, so that reliable in the field. Today, a multiline addressing control of the dispersion can be achieved with technique, invented at RRI, is extensively used sufficient repeatability for high technology in LCD electronics worldwide. The LCD lab has applications. The main advantage of LCs is their basic facilities to fabricate LC cells and small responsiveness to external stimuli like electric size prototype displays for testing purposes. and magnetic field which provides more control on the dispersion process and tunability of the nanocomposites. Currently, RHEOLOGY AND LIGHT the SCM group is working with BaTiO3, gold SCATTERING STUDIES nanoparticles and carbon nanotubes. Rheology studies the deformation and flow of Often, novel measurement techniques are matter when different kinds of stress are developed and used to measure responses in applied to the sample. Rheology builds on top varieties of liquid crystals with higher precision of the classical elasticity and Newtonian fluid and accuracy. Typical measurement techniques mechanics, to extend our understanding to involve dielectric spectroscopy, optical materials whose mechanical behavior cannot birefringence, polarizing optical microscopy be described with these classical theories. It is and others. used to make predictions for the mechanical behavior of a material based on its microscopic structure. Rheology has important applications in engineering (development and use of polymer materials), geophysics (studies of mud, snow, magma, etc) and physiology (blood flow measurements).

Researchers at RRI use rheology and light scattering techniques to study the dynamics and

42 various responses in techniques are used to investigate its stability soft glassy under stress and strain, and determine the materials. Examples temperature-concentration phase diagram. of these are various Dynamic light scatterometry techniques are concentrated used to extract the particle size distribution in suspensions, a sample. emulsions and gels, that are used widely in industry. Soft ELECTROCHEMISTRY AND glassy materials SURFACE SCIENCE exhibit slow The Electrochemistry and Surface Science lab dynamics and serve at RRI is actively involved in various research as excellent model activities related to: (i) electron transfer systems in the processes of redox molecules; (ii) electrical and understanding of photoconductivity of doped columnar discotic non-equilibrium liquid crystals; (iii) electrochemistry of surfaces glass transitions in and interfaces formed by self-assembled hard condensed monolayers and other organic thin films; matter. A mix of (iv)electron transfer processes and conductivity synthetic clay suspended in water called in bio-molecules on electrode surfaces; (v) Laponite is currently a material of interest for characterization of conducting polymer the SCM group. Laponite is also used to study nanostructures. The latter can lead to potential instabilities at the interface that occur when a applications in sensors, energy conversion low viscosity fluid (clay) is injected into a more devices and fuel cells. The lab is equipped with viscous one (water). Such studies are modern facilities allowing for a wide range of important for various technological processes measurement techniques to be applied. Some like percolation of oil through porous rocks. of the extensively used equipment include Amphiphilic compounds consist of molecules atomic force microscope, scanning tunneling that have both hydrophobic and hydrophilic microscope, electrochemical quartz crystal parts. At high enough concentrations the microbalance, frequency response analyzer amphiphilic molecules start to form micelles or and more. vesicles (amphiphilic molecules group together in various 3D structures arranged with their hydrophilic part facing the solvent). Amphiphilic block copolymers are a type of copolymer that is used in pharmaceutical applications for sustained–release technologies or gene delivery. Because of their amphiphilic nature when suspended in aqueous solution they start to form micelles. The hydrophobic core of the micelles serves as a reservoir for hydrophobic drugs. Pluronic triblock copolymer is a type of amphiphilic copolymer that is extensively studied by researchers at RRI because of its enormous potential for controlled drug delivery applications. Rheology

43 BIOPHYSICS phenomenological theory of phase transition in lipid bilayers has been formulated by The Biophysics lab was started just two years researchers at RRI. A study of the structural ago. Today it’s a self-sufficient lab where cells changes induced in lipid bilayers bound to can be grown, manipulated and analyzed. The toxins and the development of a new primary research focus in the Biophysics lab is technique to extract their electron density the understanding of cellular dynamics like profiles is underway. force generation, movement and transport processes. A variety of cells is grown in the lab and tested using novel experimental LIQUID CRYSTALS THEORY techniques. Members of the Biophysics lab are currently involved in the design, construction Theoretical work is conducted by many of the and integration of an experimental set up that SCM group members parallel to their can provide insight into the deformations and experimental projects. Analytical models are dynamics of axons. Axons are a part of the being developed for the behavior of various neuron that extends from the neuron’s cell liquid crystals, membranes and polymers. body. In the majority of cases, they are found to transmit electrical pulses, forming the transmission lines of our nerve system. Experimental research of the patterning and differentiation of stem cells is another important activity in the Biophysics lab.

PHASE BEHAVIOR OF SURFACTANTS

Surfactants are amphiphilic organic compounds that allow easier spreading between two liquids or a liquid and solid. They are widely used in our everyday life as detergents, foaming agents and emulsifiers. The research endeavor of the SCM group are focused on fundamental understanding of the phase behavior of various surfactants with equal emphasis on interpretation of experimental results and development of analytical models.

Lipids are a group of molecules that form an important structural component of cell membranes. Their main biological function includes energy storage and “signaling”. A lipid bilayer is made up of two layers of lipid molecules to form a continuous barrier around the cell called membrane. The cell membranes of almost all living organisms and many viruses are made of lipid bilayers. Recently, a

44 CHEMISTRY LAB

Sandeep Kumar is specializing in synthesis of liquid crystals in the Chemistry Lab at RRI. His last year’s individual and collaborative research efforts have led to the synthesis and characterization of numerous new novel mesogens with more than a dozen papers published in highly reputed international journals.

The synthesis and characterization of two series of novel triphenylene-based benzene- bridged symmetric discotic dimmers was reported. The thermotropic liquid crystalline properties were investigated by polarizing optical microscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. DC conductivity of charge transfer complexes at two ratios was studied as a function of temperature. Parallel to this work, the design and synthesis of novel banana- discotic dimers and banana-bridged discotic dimers was also presented. The chemical structures have been characterized by spectral techniques and elemental analysis. The thermal behaviors of the compounds have been investigated by polarizing optical microscopy and DSC. None of these synthesized compounds exhibited any liquid crystalline property probably because of the incompatibility of the bent-core with the discotic core.

A nanophase segregated layered phase (SmA) with alternating calamitic and discotic layers was observed for the first time in novel linked disc–rod oligomesogens, containing six cyanobiphenyl moieties radially-attached to a central tricycloquinazoline discotic heteroaromatic core via flexible alkyl spacers.

In collaboration with researchers from Malaysia and Germany, a variety of liquid crystalline materials having azobenzene groups were prepared and characterized using polarizing optical microscopy, DSC and XRD. The trans- form of azo compounds showed a strong band in the UV region (355-369 nm) and a ongoing research

45 Organic Chemistry Lab were carried out by Arun Roy and his collaborators. This compound exhibited two orthogonal Smectic A phases with decreasing temperature. Though the lower temperature phase is characterized as the antiferroelectric Smectic A phase, the structure of the higher temperature phase is yet to be understood. Arun Roy and his weak band in the visible region (460-470 nm). collaborators investigated experimentally the This suggested that photochromism (reversible structure of these phases and are currently transformation of a chemical substance developing a theoretical model to describe the between two forms with different absorption experimental results and the influence of an spectra by the absorption of electromagnetic external electric field on the structures. radiation) may be achieved by the introduction In collaboration with Soma Datta (post of the azo linkage in different liquid crystals doctoral fellow at RRI), Arun Roy conducted molecules. dynamic measurements of electroclinic response in the chiral Smectic A* liquid crystals in the vicinity of the transition from the PHYSICAL MEASUREMENTS LAB Smectic A* to Smectic C* phase using a new Arun Roy is a research scientist at RRI and part electro-optic technique. The experimental of the Physical Measurements Lab. Along with technique took into account the nonlinearity Prathiba’s group, he conducted flexoelectric of the electroclinic response close to the studies on mixtures of compounds made of transition temperature and allowed for the rod-like and bent-core molecules. The measurement of the electroclinic coefficient, flexolectricity in nematic liquid crystals made relaxation frequency and the nonlinear of bent-core (BC) molecules raised interest as coefficient of the electroclinic response. It was the flexoelectric coefficient of such liquid found that the electroclinic coefficient crystals had been measured recently and diverged with decreasing temperature as the indicated three orders of magnitude larger Smectic A* to Smectic C* phase transition values than that of the calamitic compounds. temperature was approached. This large value of the flexoelectric coefficient Azo functionalized materials are of special may lead to applications in novel sensors and interest, due to their photosensitive nature, microelectric power generators. However, which could be exploited for optical and most compounds made of BC molecules do optoelectronic devices. If not exhibit nematic phase. The flexoelectric such materials also possess properties of a binary mixture of a calamitic liquid crystalline properties, compound (8OCB) and a compound with BC then they have increased molecules were studied. Further details of this potential for technological work can be found in their paper published in applications. Such future Applied Physics Letters this year. opportunities have lead Recently, BC compounds exhibiting orthogonal Arun Roy and his team to Smectic A phases with transversely polarized the synthesis of five new layers have been discovered and their potential series of azo functionalized for applications in new generation liquid crystal compounds formed by displays has been discussed. Experimental covalent bonding. The studies on a new BC compound synthesized in structure and

46 mesomorphic properties of these compounds exhibit DC phase and a glass transition at lower revealed that they contain both symmetric and temperatures. The technique used by the non-symmetric molecules and exhibit mainly group is dielectric spectroscopy. The specimen nematic and columnar mesophases. The was synthesized recently in the Organic nature of these mesophases is investigated by Chemistry Lab. polarizing optical microscopy (POM), Last year Pratibha’s PhD students, guided by differential scanning calorimetry (DSC) and X- their advisor, conducted experiments to study ray diffraction (XRD) techniques. Preliminary the macroscopic orientational order in a binary and qualitative investigation on the mixture composed of rod-like and bent-core photosensitivity, dielectric and optical molecules. Optical birefringence transmission of the mesophases of one of measurements in a rod-like (R) compound and these compounds were also carried out. its mixtures with a compound made of bent- Research on dispersions of nanoparticles (NPs) core (BC) molecules were carried out. Infrared of ferroelectric materials like BaTiO3 and Sn2P2S6 in liquid crystals (LCs) is being pursued very actively by researchers from the Physical Measurements Lab, because of possible practical applications. The stability of these liquid crystal-nanoparticle (LC-NP) dispersions over extended periods of time is very crucial for the proper functioning of any practical device. However, making a stable dispersion of such nanoparticles in liquid crystals is a complex process and the physical properties of these composite materials appear to depend on the preparation conditions. Thus, the reproducibility of the experimental data on the LC-NP dispersions is difficult and some dichroism technique was used to analyze one conflicting results have been reported in the of the mixtures. literature. Studies were done on the stability of Pratibha is collaborating with researchers from the nematic and smectic phases in the LC-NP University of Colorado, Boulder, CO, USA in the dispersions consisting of the calamitic investigation and further understanding of compound (8OCB) doped with ferroelectric tunable optical metamaterials. Metamaterials BaTiO nanoparticles. Different preparation 3 composed of plasmonic metal nanoparticles conditions on making a stable dispersion of and liquid crystals (LCs) have a high potential ferroelectric nanoparticles in 8OCB have been to form tunable optical metamaterials. investigated. Plasmonic metal nanoparticles exhibit The dark conglomerate (DC) phase refractive index tenability while the properties characterized by a spontaneous formation of of liquid crystals can be tuned by the action of chiral domains by achiral molecules is observed external fields. Such metamaterials have the in some liquid crystals made of bent-core advantage that their mass production is much molecules. Not many physical studies of this faster and cost effective compared to those intriguing phase are yet available. R Pratibha formed by nano lithographic techniques. and her colleagues are now involved in a However one of the major challenges is to detailed investigation of the dielectric obtain good dispersion of the NPs in the liquid properties of bent-core liquid crystals that crystal matrix. Their previous work on

47 dispersions birefringence of gold and nanospheres diamagnetic (GNS) in anisotropy smectic were studied liquid as a function crystals has of shown that temperature not only is it (the possible to form stable uniform LC-GNS temperature range was chosen around the dispersions without any aggregation of the nematic-isotropic (NI) transition). CNT bundles GNSs but it is also possible to tune the optical were found to increase with increased properties as a function of the volume fraction concentration of SWCNTs. Polarized optical of the GNSs. To facilitate further the microscope (POM) studies on these composites composition of such metamaterial, it is of to look for the alignment of CNT bundles near fundamental interest and importance to NI transition temperatures are in progress. understand what are the reasons for the Very few direct measurements of magnetic enhanced stability of the GNSs in layered susceptibility in the surfactant based lyotropic smectic liquid crystals. Last year, the team liquid crystals (LLC) have been reported. In made a careful analysis of a set of AFM data 2005, Vijayaranghavan carried out a direct which revealed smectic layer deformation measurement of diamagnetic susceptibility profiles caused by the GNSs in thin films of the using a Faraday balance on an ionic surfactant LC-GNS dispersions. The study also based LLC. Systematic susceptibility studies demonstrated that spatial structuring of the were done on the system using SAXS and/or nanoparticles can be used as a tunable Light Scattering technique. The results revealed parameter in LC-GNS dispersions. a correlation between the micellar sizes and D Vijayaranghavan is a scientific officer in the shapes to the susceptibility. The diamagnetic SCM group. His research interests lie in the field anisotropy behavior in the nematic phase was of nanoparticle-liquid crystal composites, their also analyzed. physical and in particular their magnetic properties. During the year, he concentrated his efforts on studying the physical properties LIQUID CRYSTAL DISPLAY LAB of liquid crystal-nanoparticle composites, T N Ruckmongathan runs the Liquid Crystal diamagnetic properties of lyotropic liquid Display Lab where his group is concentrated on crystals and high magnetic field experiments. the development of new addressing The first theme involved magnetic techniques to reduce power dissipation and susceptibility, optical birefringence and hardware complexity of drive electronics in electrical conductivity studies of a nematic passive matrix LCDs. An application for an liquid crystal doped with different Indian patent related to bit-slice addressing concentrations of carbon nanontubes. The and local switching of backlight techniques was samples were provided by Kumar from the sent in January 2010. Most LCDs use backlight Organic Chemistry Lab. It is known that and much power is wasted illuminating the nematic liquid crystals (LC) can be used as dark pixels. The bit-slice addressing is a serial aligning agents for single walled carbon approach to driving LCDs, that combines nanotubes (SWCNTs) and the presence of intensity modulation backlight for each bit of SWCNTs, in return, increases the nematic grey to reduce hardware complexity. The DAC ordering of the liquid crystalline molecules. The

48 in LCDs can be replaced with voltage level shifters to switch pixels ON or OFF depending on the gray shade bit to further reduce the hardware complexity of data drivers. About 80 to 90% of power is consumed by the backlight in LCDs. A maximum of 40% and an average of 26% reduction in power consumption of backlight was achieved for 27 standard images used for image processing by switching OFF backlight illumination whenever grey shade bit was zero for all pixels in a cluster of 256 (16 x 16) pixels.

Ruckmongathan is also exploring the possibility for applying compressive sensing to displays. The motivation for this work is the ‘single pixel consisting of a periodic stack of bilayers camera’ that uses optical mask and a photo separated by water. Different lamellar phases detector for compressive sensing. Display is were observed as a function of temperature. the inverse process of sensing; as such there is Although there have been quite a few no breakthrough till today. attempts at formulating a phenomenological theory of transitions between these phases, none of them is able to explain all their X-RAY DIFFRACTION LAB experimentally observed features. The theory developed by the group was able to account V A Raghunathan is the head of the X-ray Lab for all the salient structural features of these within the Soft Condensed Matter Group. He phases. conducts fundamental research in the area of phase behavior of surfactants using both Many toxins, such as cholera and shiga toxin theory and experimental results for his gain entry into the host cell by inducing interpretations. Last year, a collaborative work tubulation of the plasma membrane. with his PhD student Arif Kamal and Madan Experiments using model membranes show Rao led to the development of a that such tubulation occurs only with certain phenomenological theory of phase transitions class of lipids. This lipid specificity is currently in lipid bilayers. Many lipids of biological origin not understood. A systematic study of self-assemble in water to form lamellar phases structural changes induced in lipid bilayers by bound toxins has been initiated by Raghunathan in collaboration with researchers from Curie Institute, Paris, France. In the first stage of this study, both cholera and shiga toxins were found to increase the lamellar periodicity of the lipid bilayers on binding. The conditions under which non-lamellar structures would be stabilized in these systems is being currently probed. Such non-lamellar structures would play an important role in the tubulation of the plasma membrane.

Amphiphilic molecules self-assemble in water to form aggregates of various morphologies,

49 such as spheres, cylinders and bilayers. In these systems the lamellar periodicity is addition to these well-known morphologies, comparable to the wavelength of visible light some of these systems also form a network of and hence they display iridescence. Such cylinders over narrow regions of the phase systems have been of interest to both – the diagram. Raghunathan’s group has recently cosmetic industry and Raghunathan. While found some surfactant-water systems where studying the stability of a swollen lamellar these catenoid phases occur over a wide range phase of the ionic surfactant alkenylsuccinic of composition. Further, temperature driven acid (ASA), it was found that small amounts of transitions between catenoid phases of a non-ionic surfactant could lead to the different symmetries have also been observed collapse of this phase. Bridging interactions for the first time. Experiments are underway to between the bilayers, arising from hydrogen understand the role of different structural bonding of the polymer to the acid headgroup parameters of the surfactant in stabilizing of ASA is responsible for the collapse. Similar these phases. A phenomenological model for mechanisms could be involved in fusion of lipid phase transitions in these systems is also being vesicles, where the apposing membranes have developed. to be brought into close proximity for fusion to occur. The electron density profiles (EDP) of lipid bilayers may be calculated from X-ray diffraction data using Fourier reconstruction BIOPHYSICS LAB techniques. A few methods have been reported in the literature to determine the EDP. One of the major research efforts of Pramod While calculating the EDPs of some lipid Pullarkat’s group is probing the mechanical properties of axons. Their partners include researchers from University of Santiago,Chile and Indian Institute of Science Education and Research (IISER) , Pune, India. F. Melo, R. Bernal and P. Pullarkat developed a new flow- technique for probing the mechanical properties of Axons. A related paper has now been reviewed and published. A system which uses a novel optical fiber based force measurement technique to probe axonal mechanics was assembled last year. The necessary software to track the position of the fiber with a very high accuracy was developed in-house. Another code was written in order to interface the detectors and actuators. Chirag mixtures, Raghunathan and his colleague Kalelkar, a visiting post doctoral fellow, Georg Pabst at the Institute of Biophysics and calibrated a camera and a Position Sensitive Nanosystems Research, Austria, realized that Detector (PSD). Currently, the piezoelectric these methods give inconsistent results. A new actuator is being integrated into the system, method has been proposed which avoids after which the set up will be ready for these drawbacks and can also be extended to preliminary experiments. determine the composition of lipid mixtures. Axon instabilities are also actively studied by Many surfactants form highly swollen and looking at the mechanism behind the stable lamellar phases in water. In some of formation of roughly periodic swellings in

50 axons under induced cells. A single neurodegenerative step conditions. A electrochemical technique to method was fluorescently label the developed to various cellular prepare Pd components of nanoparticles interest was dispersed in the developed. A new flow-chamber has been conducting polymers. The method constructed, and tested. A huge amount of simultaneously produced conducting polymer effort was put into improving the cell culture stabilized metal nanoparticles in solution as techniques in order to obtain good well as a thin film of the nanocomposite on the quantitative data. Preliminary experiments surface. The electrocatalytic effect of these using various biochemical agents against nanocomposites have been demonstrated for specific axonal components have been methanol, ethanol and formic acid electro- performed. Reliable quantitative data are oxidation which are the essential anodic expected in the next six months. reactions in the low temperature direct fuel cells. Due to the excellent hydrogen evolution Another major project of Pullarkat and his property of the dispersed Pd nanoparticles, team aims at investigating stem cell this material has the potential to emerge as an differentiation in externally imposed chemical alternative to the more expensive platinum for and substrate stiffness gradients. The idea is to hydrogen generation by electrolysis. The mimic and study pattern formation in research involved extensive characterization developing embryos using stem cells. A micro using techniques like Atomic Force Microscopy fluidic system to sustain concentration (AFM), FTIR, surface XRD, XPS and gradients was developed and cell viability in electrochemical studies. For practical such conditions was verified. Thin (100—500 applications in fuel cells, the nanocomposite microns) sheets of gels with varying stiffness film needs to be coated on a graphite are being prepared and their Young’s moduli substrate, which is less expensive and measured. Current activities involve developing preferred substrate material. The stiffness gradients and looking at cell electrocatalytic effect on alcohol oxidation in responses in stiffness/chemical gradients. acidic as well as alkaline media for these coatings on graphite substrate was investigated. The studies showed that the film ELECROCHEMISTRY & SURFACE SCIENCE LAB

V Lakshimnarayanan’s time at work is spent mostly in the Electrochemistry and Surface Science Lab. Significant time and effort of his group last year went into the electrochemical synthesis of the so called “metal nanoparticles impregnated conducting polymer films”. Metal nanoparticles such as Palladium and gold dispersed in conducting polymers possess excellent electrocatalytic properties, which find potential applications in sensors, energy conversion devices and fuel

51 Study of Photoconductivity of Discotic and Doped Discotic Liquid Crystals is a joint effort between Lakshminarayanan, Kumar and G Kavitha. Polymer organic photoconductors have been used as photoconductive media in the field of xerography and laser printing. The efficiency of photocopier and laser printers is due to the mobility of charge carriers in the photoconductive layer, coated on graphite can also be effective as therefore a lot of effort goes into the catalyst material for fuel cell applications. development of such organic photoconductors. Currently, the focus is on Using a simple one –step electrochemical designing an instrument to measure the process, it is possible to form a thin film of photoconductivity of liquid crystals. Direct gold nanoparticles on metal surfaces photocurrent measurement as a function of possessing very high electrocatalytic activity temperature was set up and fruitful results of for alcohol oxidation in alkaline media. Due the dark conductivity and photoconductivity of to its nano scale geometry, the Au pure as well as doped triphenylene were nanoparticles coated surfaces are expected to obtained. Such materials can also find behave differently for the study of electron potential application in organic thin film solar transfer processes when compared to the cells. This work is in a preliminary stage and is normal planar electrodes. Lakshminarayanan’s expected to provide some new exciting group examined the behaviour of classical findings in the near future. reversible redox systems on a surface coated with Au nanoparticles and demonstrated the potential of such a surface as a bio-sensor for RHEOLOGY AND LIGHT glucose and dopamine which is an important SCATTERING LAB neurotransmitter. Ranjini Bandyopadhyay is a research faculty One of the areas of intense research in soft member of the SCM Group and the head of condensed matter is the study of electrical the Rheology and Light Scattering Lab. Her conductivity of biomolecules such as DNA and research group employs dynamic light proteins. In this regard, Lakshminarayanan scattering, rheology, optical imaging or a looked at STM images for the redox proteins combination of these techniques to study the such a cytochrome-c and myoglobin when structures, dynamics, stability and mechanical immobilized on gold surface. The surface responses of a diverse range of soft materials. features were of several tens of nanometers In a recent paper published online in Soft which clearly pointed to the possibility of Matter, she discussed the stress relaxation of electron tunneling through the protein aging colloidal glasses. Concentrated molecules. This prompted a study of the suspensions, emulsions and gels exhibit rich electrical conductivity of the redox protein physical behavior and are widely used in the cytochrome-c. The current – voltage industry. Generically, these materials, characteristic was measured using scanning characterized by slow dynamics, are classified probe microscopy. The results obtained as soft glassy materials. The motivation for this confirmed the electrical conductivity of heme work came from the fact that these soft glassy proteins and further work is under way to materials serve as excellent model systems in understand this mechanism. the understanding of the non-equilibrium glass

52 transition in hard condensed matter systems. standard tools of fluid mechanics will be used The relaxation phenomena of such systems to understand the transition between the were studied by analyzing the temporal Saffmann Taylor and the crack propagation behavior of the response functions to an regimes. applied step strain. The results demonstrated While the structural differences between a gel that this method is an excellent alternative to and a glass are well known, the aim of another light scattering experiments in understanding of Bandyopadhyay’s projects is to identify the the relaxational dynamics of soft glassy differences in the rheology exhibited by the materials. gel and the soft glassy phases. In synthetic clay Pluronic block copolymer micelles have an samples of Laponite or Bentonite, soft enormous potential as drug delivery agents. repulsive glasses form above a critical clay The association of additives with Pluronic concentration under very low or no salt macromolecules is therefore a very interesting conditions. Gels, which can be thought of as topic and recent experiments have studied the tenuous interconnected networks, form when aggregation of Pluronic micelles in the the repulsion between individual particles is presence of the drug Ibuprofen. In particular, screened by adding salt. Having established an understanding of the interaction between the presence of soft glassy rheology in copolymers and surfactants is important due Laponite suspensions, extensive experiments to the wide use of polymer-surfactant were performed on Laponite and Bentonite mixtures in the manufacture of paints, detergents, cosmetics and pharmaceuticals. Using dynamic light scattering and rheometry, Bandyopadhyay investigated the changes in the mechanical moduli of a Pluronic solution on the addition of the anionic surfactant. The results are to be published in a peer-reviewed journal soon. The group’s future intentions are to explore the potential of Pluronic as a drug delivery agent.

When a low viscosity fluid is injected into a more viscous fluid, (as in injecting water in glycerine), an instability called the Saffmann Taylor instability is created. The understanding suspensions over a range of clay of this instability is important because of the concentrations with and without added salt ubiquity of such processes in technological (NaCl). From the microscopy data, it is applications, such as the percolation of oil in expected that an NaCl vs. Bentonite porous rocks. Bandyopadhyay has started a concentration phase diagram could also be project the main purpose of which is to constructed over a wide range of Bentonite investigate the physics behind the pattern and NaCl concentrations. formation at the quasi-two dimensional interface between a Newtonian fluid (water), Bandyopadhyay’s other interests this year and an aging non-Newtonian fluid (an aqueous include the rheology of concentrated suspension of the synthetic clay, Laponite). cornstarch suspensions, light scattering from The role of the rate of injection of water into polystyrene beads dispersed in aging Laponite the cell containing the Laponite on the suspensions (done in collaboration with patterns formed will be investigated. The researchers from the Theoretical Physics Group

53 at RRI) and the effects of base roughness on the motion of vibrated granular beads.

THEORY OF LIQUID CRYSTALS

Yashodhan Hatwalne conducts research in the wide field of soft matter physics. His work this year was both analytical as well as experimental in nature. A recent paper was published describing the laser induced rotation of trapped chiral and achiral nematic droplets. to the formation of GUVs is not understood, Manipulation of suspended micron- sized fluid and the method is a mere recipe. Hatwalne’s droplets by light is interesting for fundamental group was motivated to make a headway in reasons as well as for applications such as understanding this mechanism. They found optical switches. Chiralised as well as achiral that the first step in the electro-formation nematic droplets suspended in water and in process (hydration of the dried surfactant on a glycerol solution were manipulated with lasers. platinum wire, or a cover slip) is in itself very It was found that chiralised nematic droplets complex, exhibiting some previously unknown can be set into rotation using plane polarised instabilities. The process of hydration lead to light. The difference in the law followed by the very interesting structures that were rotation frequency of droplets suspended in extensively studied using various microscopic glycerol solution (more viscous than the techniques. An attempt was made to describe nematic material) and those suspended in these observations using a qualitative theory water showed the importance of internal that exploited the interplay between elasticity, dissipation in the droplets. topological defects, and flow. Another of his experimental projects included On the theoretical front, Hatwalne was looking the study of growth morphologies in giant at the morphologies of polymer crystallites. unilamellar vesicles (GUVs). GUVs are Solution- grown or melt- grown polymer extensively studied and used in soft matter crystallites show fascinating morphologies. physics and biological physics. The most These structures have been observed since popular method of producing them is the so 1952, but there is no quantitative theory which called “electro-formation method”, in which adequately describes them. Hatwalne and his platinum wires coated with surfactants are collaborators - Jaya Kumar and M. hydrated under an alternating electric field. At Muthukumar, formulated a phenomenological the present time the mechanism which leads theory to explain the observed morphologies. The theory makes some interesting predictions that could be tested experimentally, and is the first complete theory which accounts for the entire range of observed morphologies.

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55 Established around 1995, the Theoretical Physics (TP) group is a vibrant community of research faculty, post doctoral fellows and students that work at the interface between mathematics and physics. There are two main distinct areas of research – gravity and statistical mechanics. Individual members’ interest within the area of statistical mechanics branch into mesoscopic physics, non equilibrium physics, soft condensed matter physics and biophysics. Research in general relativity includes gravitational waves and quantum gravity. Members often engage in collaborations among each other and/or groups of the institute that conduct experimental physics activities. The group has also created a forum for theorists to “dirty” their hands with simple table-top experiments that can express conceptual points.

The following pages summarize the major areas of research for the TP group. Each member’s individual work during the last year is provided in the next section, giving the reader more detailed and technical description of their respective research activities.

STATISTICAL MECHANICS

When a macroscopic device or a sample of bulk material are scaled down to mesoscopic size (from few microns to the size of a single atom), they begin to reveal quantum mechanical effects. As a result, their properties might be very different from the ones of their bulk counterparts.

Research at RRI is focused on the development of a theory of heat and electron transport in such mesoscopic scale systems. Part of that work includes analytical and numerical treatment of the Fourier’s law of heat conduction in disordered harmonic and anharmonic crystals. Theoretical and experimental research in that field is important for the advancement of our fundamental understanding of the transport properties of materials, which in turn would lay the overview

56 foundation needed for improving the In general, sources of gravitational waves are performance of nanodevice applications and bodies with strong time dependent technologies. gravitational field. These include binary star systems composed of white dwarfs, neutron The development of fast algorithms for stars or black holes. The orbiting bodies of estimation of the probability of rare events is such systems continually lose energy while part of the ongoing research in the field of non radiating gravitational waves. This leads to equilibrium statistical mechanics. Developed in decrease in the distance between the bodies the context of physics, such algorithms are also forcing them to rotate more rapidly, thus important in other areas like finance and cellular increasing their loss of energy to gravitational processes in biology. radiation. For systems like the Sun-Earth one may find this effect to be negligible on the time scales of the Universe. The closer the BIOLOGICAL PHYSICS bodies in the binary system, the larger this Various topics in the field of biophysics have effect is, leading eventually to a collision that attracted the interest of the TP group. Here can result in a merger or the creation of a again is an example of the value of having a black hole. Such binaries are referred to as relatively small institute with a wide range of inspiralling binaries because the bodies in the professional research interests and scientists binary system describe a spiral as they who are open-minded, and eager to move into approach each other. new areas and apply their experience to LIGO stands for Laser Interferometer related fields. Current activities in biophysics at Gravitational-wave Observatory and is a joint RRI are focused on mitochondrial distribution scientific experimental project attempting to dynamics, vesicle formation and the detect directly gravitational waves. The project development of analytical models to describe is led by scientists and engineers from MIT, DNA elasticity (stretching, twisting and various Caltech and other universities. VIRGO is another deformations). Membranes, and transport of interferometer aiming at direct gravitational materials in the cell are other topics which has wave detection which is a result of the effort been pursued at RRI. Research in this area of various European institutions. Both these involves active collaboration with experimental instruments are built and tested and have groups in NCBS (National Center for Biological achieved their design sensitivities. The signals Sciences) and on campus. expected are extremely weak and buried in noise. A major challenge now is the accurate calculation of the expected gravitational GRAVITATIONAL WAVES waveforms from the observed binary systems. The existence of gravitational waves was Later, these waveforms are cross-correlated predicted by Albert Einstein’s theory of general with the observational data in order to extract relativity in 1916. Their existence is inferred the gravitational wave signature. Researchers using indirect methods but they have not been at RRI are currently looking at ways to precisely measured directly yet. The direct detection of calculate the gravitational waveform from few such waves will help scientists test general inspiralling binaries. In future, these are relativity more thoroughly. More importantly, it expected to improve the sensitivity of other will open a new “eye”, with which we may envisioned space instruments aiming at observe objects and phenomena in the detecting gravitational waves like LISA (Laser Universe that stay invisible for the optical and Interferometer Space Antenna). radio astronomy.

57 QUANTUM GRAVITY In his early days, Einstein believed that the Universe was static. His general relativity theory At present, the formulation of a theory of was predicting otherwise, so he added a term quantum gravity engages and challenges the called the cosmological constant that made minds and creativity of many scientists in the the Universe static. Later on, Hubble provided theoretical physics community. Quantum observational proof that the Universe was gravity (QG) is envisioned to be a self expanding and Einstein abandoned the consistent theory that will quantize the gravity cosmological constant calling it the “biggest field thus combining the two major theories of blunder” in his career. Recently, the interest in quantum mechanics and general relativity. the cosmological constant among There are a handful of QG theories being cosmologists and theoretical physicists has developed in parallel like the string theory, increased mainly because its inclusion as a loop quantum gravity or causal set theory. cosmological parameter significantly improves Research at RRI is focused on the last two the agreement between theory and approaches to quantum gravity. observation. Loop Quantum theory proposes that all the The gravitational pull of matter is expected to space where physical phenomena happen be slow down the expansion of the universe. represented by continuity of finite quantized Surprisingly, observations of supernovae loops of excited gravitational fields called spin indicate that the universe expansion is networks. Unlike string theory, loop quantum accelerating! Such results, though preliminary gravity (LQG) doesn’t try to unify all four major in nature, raise the possibility that the universe forces (electromagnetic, gravitational, strong contains an unknown form of matter or nuclear and weak nuclear force). The major energy that is gravitationally repulsive. The challenge for LQG comes from the fact that cosmological constant may describe such quantum theory relies on a reference matter or energy, but a lot more work remains (background) space-time, while general before cosmologists and theoretical physicists relativity is said to be background can throw light on this mystery! Another independent. The approach of LQG is to reason for the reintroduction of the formulate quantum mechanics without relying cosmological constant is that the estimated on the space-time reference. Members of the age of the universe (with the amount of Theoretical Physics group at RRI develop new matter we observe) by cosmological models mathematical tools and ideas as steps towards that don’t take it into account is less than the the development of a true theory of quantum age of the oldest stars we observe. When the gravity. cosmological constant term is added to the Causal Set theory is another approach to standard theory of Big Bang it becomes quantum gravity. Its founding principle states consistent with various astronomical that space-time is fundamentally discrete and observations. Building on the work of Sorkin, the relations between space-time events are who suggested that the observed cosmological causal. Members at RRI with a focus of the constant may be due to quantum gravity causal set theory investigate classical stochastic fluctuations, researchers at RRI pursue an growth modes, topology and dynamics of the analogy between that elusive term in the causal set in their attempt to construct a theory of general relativity and the surface consistent quantum theory of causal sets. tension of fluid membranes. This is yet another Parallel to that, investigations of the observer- example of the collaborations that emerge at independent alternative formulation of the Institute due to the interactions between quantum theory are currently being members with different fields of research. conducted.

58 STATISTICAL MECHANICS

Abhishek Dhar conducts active research in the field of statistical mechanics and soft matter physics focusing mainly on the development of a microscopic theory of heat and electron transport. Collaborating with Dibyendu Roy and scientists from IISc, he studied mesoscopic systems trying to understand electron transport across small devices such as quantum dots in situations where the interactions between electrons are strong. For a simple model of spinless interacting fermions, two new phenomena - a two-particle resonance effect and diode-like behavior were investigated.

Fourier’s law of heat conduction is a phenomenological law and it does not have a rigorous microscopic derivation. Last year, Dhar worked along with researchers from USA, Germany and Japan on the open problem of finding what were the necessary conditions under which Fourier’s law was valid in three- dimensional systems. In crystalline solids, lattice vibrations (phonons) are the carriers of heat and two important mechanisms for scattering of the phonons – anharmonicity and disorder were studied to find out if they can lead to a finite heat conductivity of the crystal. In the case of heat conduction in disordered harmonic crystals, the system size dependence of thermal conductivity was addressed and analytic results obtained. These results were then tested through extensive numerical calculations and simulations. A conflict between the two currently poses a challenge before the group. In the case of heat conduction in anharmonic crystals, nonequilibrium simulations in a three dimensional anharmonic lattice were done. The results confirmed the three dimensional system had finite thermal conductivity thus providing the first verification of Fourier’s law. ongoing research

59 The rising faster compared to other direct simulation interest in methods. everything Samarth Chandra joined the institute as a post “nano” has doctoral fellow in November 2009. His areas of brought the current professional research interests are need to statistical mechanics and biophysics. Since understand becoming a member of the Theoretical Physics and measure Group at RRI, he has developed an algorithm the heat for finding approximate ground states of a transport in spin glass of classical continuous spins which low- are much closer to experimental reality than dimensional the Ising spin case. This algorithm is systems such as independent of the dimensionality of the nanowires, lattice. In the future he plans to implement this nanotubes and algorithm to study the properties of spin glass graphene. Some interesting data on thermal ground states for three or higher dimensional conductivity in n-type In-As nanowires were lattices. Samarth has also formulated a recently obtained by a group in TIFR. Results method for constructing classical spin models showed that the thermal conductivity was for given states as ground states. Future work about 1000 times smaller than bulk samples includes studying of these models with while the electrical conductivity was almost interesting, non-trivial ground states where unaffected. Also, the applied gate voltages some novel low temperature behavior is were found to have a strong effect on the expected. thermal conductivity. Dhar is part of a team working towards thorough interpretation of these results. BIOLOGICAL & SOFT Sanjib Sabhapandit focused his research last CONDENSED MATTER PHYSICS year on the development of an algorithm for Joseph Samuel is a mathematical physicist finding probabilities of rare events and its who works in the fields of general relativity, application to non-equilibrium processes. He optics and soft condensed matter physics. He and Dhar tested the algorithm on steady state uses geometry and topology to describe particle and heat transport in model systems. physical phenomena and this thread ties The algorithm performance was significantly together his diverse fields of research. One of his main interests last year was in the elasticity and statistical mechanics of DNA. There are single molecule experiments which probe the elastic properties of DNA by pulling and twisting them. The interpretation of these experiments requires special attention because of the geometric and topological subtleties of the writhe in the DNA. In collaboration with Supurna Sinha, he is working towards solving simple theoretical models and extracting their experimental predictions.

The team of Samuel, Sinha and Katti pursued the analogy between the cosmological

60 constant of the Universe and the surface tension of fluid membranes. The analogy developed earlier was refined by computer simulations which showed that the surface tension of a fluid membrane has statistical fluctuations stemming from its discrete molecular structure. According to them, this implies that a fluctuating cosmological constant is a generic feature of quantum gravity models and goes beyond the specific context in which it was originally proposed. This work is interdisciplinary in nature and tries to understand abstruse quantum gravity effects in using simpler systems which are better understood. phase equal to half the solid angle traced out on the Poincare sphere by a pair of photons. Supurna Sinha is a research faculty member of Local measurements at either detector do not the TP Group whose major research interests reveal the effects of the phase, which appears are focused in the field of statistical mechanics only in the coincidence counts of the two and its applications. In collaboration with detectors and is a genuinely multiparticle and Joseph Samuel and Poonam Mehta she put nonlocal effect. The phase is an optical analog forward the proposal of a polarized of the multi-particle Aharonov-Bohm effect interferometer experiment which measures which has been measured in Quantum Hall the nonlocal Pancharatnam phase acquired by systems. a pair of Hanbury Brown-Twiss photons. The experimental setup involves two polarized Narendra Kumar is a Homi Bhabha thermal sources illuminating two polarized Distinguished Professor at RRI whose research detectors. Varying the relative polarization interests are generally in randomness, angle of the detectors introduces a geometric dissipation, and decoherence in condensed matter. Last year, he tackled the problem of light transmission through a slow wave medium. Wave compression, amplification, energy storage and its delayed transmission through a low wave medium was studied analytically based entirely on the continuity equation for the optical energy flux. Results provided a phenomenological understanding of some recent experiments on light storage and its delayed transmission through a magnetically tunable ferrofluidic medium.

Madan Rao’s research is focussed on driven collective phenomena in materials and the cell. His research deals with descriptions of the dynamics and steady states of systems driven far from equilibrium, especially in the context of solids, soft materials and cells and tissues. In the context of driven solids, Rao and Surajit

61 Sengupta from IACS, Kolkata have been dynamics of fission and fusion of organelles, working on understanding the properties of regulate the flux of composition, momentum, solids driven as a result of structural energy and information.Rao has been transformation and/or external stresses. The engaged in developing a theoretical study has revealed unusual connections framework, called active hydrodynamics, to between the physics of such systems and address the relationship between fluxes and glasses and granular media. forces in a variety of contexts, where activity plays a significant role. Using this framework One other major subject of study is the Rao along with other collaborators from RRI, elucidation of theoretical approaches in cell NCBS and IISc. have studied the mechanical biology, specifically in the physics of active, response, pattern formation, symmetry evolving systems, i.e., systems comprising breaking and hydrodynamic instabilities in both molecular processes fuelled by a steady in-vivo and in-vitro reconstituted active throughput of energy. The main interest is in systems. the organization, flow and processing of chemical composition, mechanical stress, energy and information in living cells and GENERAL RELATIVITY & tissues. These new physical principles are a QUANTUM GRAVITY consequence of the novel response of cellular systems to local active forces which maintain it Bala Iyer conducts mainly theoretical research away from equilibrium. These active forces in the field of general relativity and arising from (i) the coupled dynamics of the gravitational waves. His last year’s research cytoskeleton, motors and cytoskeletal included parameterized tests of post- regulatory proteins, and (ii) the active Newtonian theory using Advanced LIGO and Einstein Telescope. General relativity has very specific predictions for the gravitational waveforms from inspiralling compact binaries obtained using the post-Newtonian (PN) approximation. Measurement of the PN coefficients is possible with the second generation gravitational wave detectors such as the Advanced LIGO, and the third generation gravitational-wave detectors such as the Einstein Telescope (ET). The extent to which such measurements could be used to test post-Newtonian theory and put bounds on a class of theories which differ from general relativity was investigated. This work was done in collaboration with Chandrakanth Mishra and researchers from Washington University, St. Louis, and Cardiff University.

Recent breakthroughs in numerical relativity enable one to examine the validity of the post-Newtonian expansion in the late stages of binary inspiral. Previous work on factorized re- summed waveforms by Damour, Iyer and Nagar showed that they achieved better

62 agreement quantum with dynamics in the numerical Loop Quantum results than Gravity (LQG) the model, and conventional argued that the Taylor definition of expanded quantum post-Newtonian waveforms. Iyer and Ryuichi dynamics in the model missed important Fujita (currently a post doctoral fellow at RRI) subtleties. Their work was a strong indication revisited and refined that work. The that the definition of the magnetic field implications for the construction of waveforms operator in LQG must be sensitive to the for prototypical compact binary sources in (conjugate) electric flux carried by the LQG detectors like LISA were examined. quantum (spin network) states.

Fruitful collaboration between Iyer, scientists Currently, Varadarajan is working on the hard from University of Maryland and Cardiff problem of defining quantum dynamics in University investigated the (dis)agreement LQG and the black hole information loss between different PN waveform families in the problem. The latter is being studied in context of initial and advanced gravitational- collaboration with A. Ashtekar from Penn State wave detectors. For their study they used University and V. Taveras from Luisiana State waveforms employed currently by Initial LIGO/ University. Virgo project. The orbital evolution of an Sumati Surya’s research is focused on the inspiralling compact binary cannot be specified causal set approach to quantum gravity and uniquely due to the inherent freedom in the related question of quantum interpretation in choice of parameters used in the PN expansion the context of quantum cosmology. Last year and the method used in solving the relevant she worked extensively on quantum vector differential equations. The group tried to measure theory. The need for a measurement- quantify the differences in few time domain independent interpretation of quantum PN models and decide whether there exist theory has been most keenly felt in the study preferred families of search templates in terms of quantum cosmology. The dilemma of how of detection ability and computational cost. to interpret quantum probabilities in the Iyer’s last year’s research also includes absence of external measurements is most investigation of head-on collision of two acute when describing the physics of the early compact objects with arbitrary mass ratios universe. In her work, done in collaboration (using the multipolar post-Minkowskian with scientists from Imperial College, London, it approximation method) and the computation was shown that the quantum measure can be of the angular momentum flux from an reinterpreted as an additive measure, which inspiralling binary system of compact objects takes its values in a Hilbert space constructed moving in quasi-elliptical orbits. Both studies from the space of histories. This line of are essentially important for the comparison of investigation has a deep physical motivation, post-Newtonian results with the numerical namely that of constructing observables in relativity simulations. quantum gravity, without recourse to measuring devices. Within the standard Madhavan Varadarajan works in the field of interpretation, no physical meaning can be classical and quantum gravity. Building on a ascribed to quantum transitions in the early previous work, he and Alok Laddha (a post universe, and hence there is a strong need for doctoral fellow ar RRI), carefully analyzed the

63 a Poonam Mehta is currently a post doctoral measurement fellow investigating the unique properties of independent neutrinos - one of most elusive and hard to formulation. detect elemental particles. Another active area Within the of her research involves geometric phases. A quantum major property of the neutrinos is their measure sustained quantum coherence over formulation, astrophysical length scales. During the last an example year, she carried out a study of general of an geometric phases in the formalism of two observable flavor neutrino oscillations. By using analogy which we can with optics and employing the Pancharatnam’s relate to prescription of quantum collapses, her study observationally led to the prediction that for the case of two is the flavors and CP conservation, the geometric expansion of phase can take only topological values and is a the universe robust quantity. However the topological from an initial hot dense state. By assigning a robustness can be destroyed once CP is quantum measure to this process, one can violated. make predictions from quantum gravity which Roman Sverdlov is another of the post could ultimately be tested by observations of doctoral fellows in the TP Group. The major the early universe. topics of his research throughout the year that Surya also addressed questions regarding the turned into manuscripts are: (i) Causal set as a low energy dynamics of causal sets. Using an discretized phase spacetime; (ii) Completely analytical continuation formulation in which local interpretation of quantum field theory; the configuration space remains Lorentzian (iii) Incorporating particle creation and (the space of causal sets), a numerical Monte annihilation into Bohm’s Pilot Wave model and Carlo type study of causal set dynamics was more. initiated. Preliminary results confirmed the predicted dominance of entropic configurations in the infinite temperature limit. The finite temperature case is currently under investigation.

It is of long standing interest in Lorentzian geometry to construct spacetime geometry and topology purely from its causal structure. While results for strongly causal spacetimes have been known for some time, there were until now only limited results for spacetimes which were future and past distinguishing, but not necessarily strongly causal. Some interesting features of these spacetimes have been examined by Surya and, in the process, a new topology was constructed purely from the causal structure.

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facilities

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65 LABORATORIES 1. RADIO ASTRONOMY LAB (RAL)

The Radio Astronomy Lab (RAL) at RRI consists of three divisions – Digital Signal Processing (DSP) Lab, Millimeter Wave and RF Lab, and X- Ray Astronomy Lab.

DSP Lab

The DSP lab is involved in the design, development and testing of digital receivers for astronomy. The DSP lab team comprises of established facilities for laser cooling and highly skilled engineers with expertise in the trapping of atoms. These include vacuum field of digital circuit design and digital signal systems, commercial and custom made lasers, processing. RRI has a long history of design spectroscopy equipment, standard electronics and development of a variety of digital and real time operating systems. A laboratory systems (receivers, spectrometers, correlators) is also set up for studying light propagation in that have improved the capabilities of national random media. Another lab hosts an and international telescope facilities. The lab experimental system to investigate quantum has modern CAD design packages for the walks of light. The system consists of three development of FPGA-based digital systems. Michelson optical interferometers, various optical components and acoustic-optical Millimeter Wave and RF Lab modulator. Two more labs allow for The engineers from the RF lab are experienced experimental research of nonlinear optical professionals with diverse skill-sets in the properties of nanocomposites and dynamics, design and development of millimeter wave and spectral behavior of laser induced and RF systems. The lab is equipped with all plasmas. Standard and custom made facilities necessary fabrication and testing facilities for in the lab include a femtosecond laser system RF systems characterization. The group has with amplifier, nanosecond Nd:YAG laser, designed and built feeds, broadband antennas spectrometers, monochromators, laser beam as well as standard and special purpose front profiler, ultra high vaccum chamber, X-ray and end receiver systems operating at wavelengths Gamma-Ray detectors, experimental set up for from decameter to millimeter. z-scan and pump probe measurements, and more. X-Ray Astronomy Lab 3. SCM GROUP LABS The X-ray lab is a fully equipped laboratory for development and testing of X-ray astronomical Chemistry Lab instrumentation. The infrastructure includes a The lab has all state of the art facilities clean room, X-ray generator, beam line, necessary for the synthesis and structure polarizer and monochromator, vacuum characterization of novel liquid crystal systems, mounts and electronics for materials. Major equipment in the lab includes performance evaluation of X-ray detectors. polarizing optical microscopes, high 2. LAMP GROUP LABS performance liquid chromatograph, differential scanning calorimeter, elemental Each faculty member of the LAMP group at RRI analyzer, infrared and UV-Visible runs lab facilities specific to his/her individual spectrophotometer. Over 700 mesomorphic research. Three of the members have well molecules have been synthesized and

66 characterized in the Organic Chemistry Lab at confocal microscope, X-ray difractometer and RRI. a small angle X-ray scatterometer.

Physical Measurements Lab Biophysics Lab

The Physical Measurements Lab is equipped The Biophysics lab is a self-sufficient lab where with standard facilities for phase transition various cells can be grown, manipulated and studies in liquid crystals, liquid crystal analyzed. It is equipped with two fully nanocomposites and various micellar solutions. motorized microscopes allowing for The lab members are actively involved in the fluorescence and face contrast microscopy development of new precise techniques for a measurements, confocal microscope, biosafety variety of phase transition measurements. cabinet for growing cells, incubators, Available equipment includes a polarizing centrifuge and a 3D microscope for optical microscope, dielectric impedance dissections. analyzer and confocal microscope. Currently, Electrochemistry and Surface Science Lab there are experimental set ups for conoscopic, switching current and various electro-optical The lab performs controlled experiments on measurements. test surfaces in electrochemical cells using electrochemical instruments such as a Liquid Crystal Display Lab potestiostat, frequency response analyzer and The LCD lab has basic facilities for fabrication lock-in amplifier. An electrochemical quartz of liquid crystal cells and small size crystal microbalance is used to measure mass (100mmX100mm) displays as well as standard changes. Thin film characterization is done electronics equipment for their testing. Spin with a variety of coating system, vacuum deposition unit, scanning probe rubbing machine and temperature controlled techniques like scanning ovens are frequently used by the lab tunneling microscopy, members. atomic force microscopy and others. Rheology and Light Scattering Lab 4. MECHANICAL The lab utilizes rheology and light scattering ENGINEERING techniques to study the dynamics of soft glassy materials and amphiphilic systems. The The mechanical most frequently used instrumentation in the workshop at RRI meets lab includes a dynamic light scatterometer and the mechanical design a rheometer. Rheology, dynamic light and fabrication needs of scatterometry and diffusing wave RRI experimental spectroscopy are some of the measurement activities. It has the techniques used in the lab. necessary machinery and a team of skilled X-Ray Diffraction Lab personnel who can The X-ray lab is set up for investigating the undertake fabrication of various sophisticated phase behavior of various surfactants using X- mechanical hardware components for ray diffraction. Polarizing light microscopy and electronics instrumentation as well as sheet small angle X-ray scattering techniques are metal work for component, receiver enclosures, often used in the lab. To perform precise X-ray and system racks. The expertise of the measurements, the lab is equipped with a mechanical workshop team has been used in large projects like the fabrication and installation

67 of 1100 helical antennas for the Mauritius Radio telescope, design and fabrication of a low frequency antenna feed system for GMRT, and fabrication of a multi-band feed for the Green Bank telescope, West Virginia. Specific tasks such as fabrication of precision mounts, positioners and cooling stages for the LAMP and SCM groups have been undertaken by the mechanical workshop team as well. Scientific Research, National Aerospace Laboratories, National Centre for Biological Sciences, TIFR Centre for Applicable LIBRARY Mathematics and others.

The library at RRI was founded by Sir C V Last year, the library repository continued to Raman and ever since has served as a constant grow. The newly included materials comprised source of both highly specialized and general of English and Hindi books, non-book knowledge for the institute members. materials, print journals and more than eighty Throughout the years, the library has online journals. Various subscriptions through continuously expanded trying to provide FORSA and the National Knowledge Resource adequate literature for the growing research Consortium of CSIR-DST facilitated enhanced activities at RRI. Currently, its total collection of access to over 4000 online journals. Papers and books and bound journals is close to 65000. PhD theses published during the year were The library has an extensive collection of added to the digital repository and a CD mirror materials in the areas of research conducted at server was added to the library to facilitate RRI – astronomy and astrophysics, classical and access to its digital products. quantum optics, soft condensed matter, theoretical physics, electronics, digital signal processing, computer science, etc. The diverse COMPUTER FACILITIES interests of the institute members are met by The various computing needs of the different collections of books on fine arts, travelling, research and development groups at Raman general science, biography and photography. Research Institute are handled by our The non-book materials of the library include computer division team. The computing scientific slides, CD-ROMs, DVDs and audio and facilities consist of multi-CPU multi-core video tapes. The role of digital information systems accessed by users from their desktops today demands flexible and adaptive librarian through a high speed internal LAN . functionality. The RRI library is a partner in Application-specific software packages along both FORSA and CSIR-DST consortia and the with development tools are available on these expansion of full text access to online journals platforms. The campus network consists of a is one of its major priorities. It also maintains a switched Gigabit backbone on fiber and wired digital repository of all publications published 10/100 Mbps Ethernet to the desktops. by RRI members as well as students’ theses Further mobility is assured by the secured and dissertations. Open Public Access Catalog wireless connection available on the campus (OPAC) is available for access to readers within premises. A dedicated 10 Mbps line ensures and outside RRI. The library participates in the constant connectivity to the global inter library networking activities with various Internet community. A computer center is also other institutions like the Indian Institute of available in the library for the needs of Science, Indian Institute of Astrophysics, students, staff and visitors. Jawaharlal Nehru Centre for Advanced

68 The computer facilities on campus continued visitors and visiting academics, including to be upgraded and improved during the last visiting doctoral students. A canteen is also year. The eight node cluster was replaced with present on campus to provide meals to all a high performance computer cluster with guests as well as lunch and refreshments to all sixteen nodes. System and application RRI employees. Various gatherings, visitor talks, packages were upgraded, and the network informal meetings, concerts and dinners take security improved. Backup and storage place at the Village – an ethnically designed requirements were addressed to meet area providing a warm rustic touch to the increased storage needs. overall atmosphere on campus.

The building adjacent to the canteen houses a small clinic where consultant medical CAMPUS practitioners pay visits at fixed hours on most The Raman Research Institute campus is days of the week. located in the northern part of Bangalore city. Sport activities are envisioned to be an The campus covers an area of around 22 acres, important part of campus life. Therefore, there where the bustling noise of the fast growing are two badminton courts available for use by metropolis gives way to the soothing sounds the research faculty, staff and students. of nature, creating the necessary peaceful environment for creative work and research. Extensive renovations of major facilities and The campus hosts all the office buildings, buildings on campus took place during the last laboratories, a canteen, guest house and the year. The Auditorium in the Main building was 10.4m telescope but when walking around one equipped with better lighting and sound is left with the impression that they are all tiny technology and the construction of a creative additions to the prevailing natural garden. space on the Library building rooftop was Most of the campus was landscaped by Sir C V finished. Currently, the canteen building is Raman and the RRI Trust is proud to enforce under major renovations that would policies that protect its unique natural modernize and upgrade it to provide quality environment. service to the institute members and distinguished visitors in a faster and more The guest house on campus has facilities to efficient manner. comfortably accommodate distinguished

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academic programs

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PhD PROGRAM

RRI offers a PhD program that gives enthusiastic and highly motivated students the opportunity to join the global research community. The unique atmosphere of intellectual freedom allows the students at RRI to pursue their individual interests within the broad areas of research conducted at the Institute. As a result, students are challenged to engage their full creative potential and develop the ability for conducting independent research. Constant formal and informal interactions with the faculty and other

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Students at RRI are registered for a PhD degree with the Jawaharlal Nehru University, New Delhi. RRI is also a participant in the Joint Astronomy Program (JAP) with the Indian Institute of Science, Bangalore and the Physics in Biology Program with the National Center for Biological Sciences, Bangalore. Further detail about the PhD program, admission requirements and process can be found on our website.

Currently, there are fifty seven students from all over India enrolled in the PhD program and conducting research with faculty members from the four groups in the institute – Astronomy and Astrophysics, Light and Matter Physics, Soft Condensed Matter Physics and Theoretical Physics.

70 Last year five PhD degrees were awarded and VISITING STUDENTS PROGRAM five were submitted for review. Raman Research Institute places high importance on its Visiting Student Program (VSP) which was introduced in 2007. VSP at RRI POST DOCTORAL FELLOWSHIP offers research experience to students, who PROGRAM are currently pursuing their undergraduate or RRI offers a post doctoral fellowship program master’s studies. The program runs year-round which is open for applications throughout the and its duration ranges from 6 weeks up to year. The initial duration of the post doctoral one year depending on individual cases. At the fellowships is two years and is often extended beginning a suitable project is identified for to three years. each student. While working on their projects, VSP students are closely advised by a research Post-doctoral fellows work independently and faculty or scientific staff member of the have the academic freedom of choice in Institute. They are encouraged to interact with research area and collaboration. Even though other staff members and graduate students post doctoral fellows are not required to work learning the importance of sharing knowledge in any specific research program or be and exchange of ideas among researchers. The attached to specific research staff of the program is designed such that students get Institute, it is desirable that they have exposed to some of the real challenges in the professional research interest and proven track world of scientific research and acquire record in areas with significant overlap or important skills that would help them in their association with the ongoing and envisaged future research pursuits. activities at the Institute. Participation of the fellows in the academic activities of the The Summer Student Program at RRI is similar Institute, student supervision as co-guides and to the Visiting Student Program but it runs collaboration with other research staff is highly only between May 1st and June 30th of each encouraged. year. It provides the opportunity to up to twenty selected candidates to become Candidates who have already held at least one involved in short term research projects under position as a post doctoral researcher can also the guidance of a research faculty member. apply for a limited number of Pancharatnam Fellowships offered at RRI. Applications are Since the program initiation, the number of accepted throughout the year and the VSP students has progressively increased processing time takes between four to six through the years. During the last year alone, a months. The selected candidates are awarded total of 101 students from different parts of the Pancharatnam Fellowship for a period of the country were part three years. of the Visiting Student Program at Further details about the post doctoral and RRI. Pancharatnam fellowships at RRI can be found on our website www.rri.res.in. All those interested to join the Visiting Currently, there are twelve post doctoral Student Program at fellows at RRI coming from across the country RRI should visit our and abroad. Their research background, website to learn more diverse scientific interests and future goals play about the eligibility important role in the overall academic and criteria and research dynamics of the institute. application process.

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people at RRI

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research faculty

ASTRONOMY AND ASTROPHYSICS

V Radhakrishnan (Distinguished A A Deshpande Dwarakanath K S Professor Emeritus) Research Interests: neutron Research Interests: Research Interests: neutron stars, pulsars & transients, extragalactic astronomy, clusters stars, pulsars, locomotion instrumentation and signal of galaxies, halo and relic radio Email: [email protected] processing sources Email: [email protected] Email: [email protected] Ravi Subrahmanyan ( RRI Director) B Ramesh Lakshmi Saripalli (RRI Trust Research Interests: Research Interests: diffuse funded position) observational cosmology, matter in our and other Research Interests: morphology extragalactic astronomy, galaxies, analog & digital signal and life-cycle of radio galaxies, antennas and signal processing processing, (sub)millimeterwave surveys ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ Email: [email protected] telescopes Email: [email protected] Email: [email protected] N Udaya Shankar (Coordinator) Harish Vedantham (Research Research Interests: sky surveys, S Sridhar Associate) detection of EoR, Research Interests: dynamo Research Interests: epoch of re- instrumentation and signal action due to turbulence in ionization, radio telescope processing for radio astronomy shear flows, MHD turbulence, instrumentation, synthesis Email: [email protected] stellar dynamics in galactic nuclei imaging Email: [email protected] Email: [email protected] Anish Roshi Research Interests: The Galaxy C R Subramanya Shashikant (Post Doctoral and Interstellar medium, Research Interests: cosmology, Fellow) Instrumentation and Signal extragalactic radio sources, Research Interests: physical processing surveys, instrumentation and cosmology, cosmic background Email: [email protected] signal processing radiation, large-scale structure of Email: [email protected] the universe Email: [email protected] R Bhandari Research Interests: topological Biswajit Paul phases, polarization optics Research Interests: X-ray Siddharth Malu (Post Doctoral Fellow) Email: [email protected] binaries, transients, X-ray instrumentation and signal Research Interests: galaxy processing clusters, cosmic microwave Biman Nath Biman Nath Email: [email protected] background Research Interests: cosmology Email: [email protected] and structure formation, extragalactic astronomy Shiv Kumar Sethi Email: [email protected] Research Interests: cosmology and structure formation, reionization era, cosmological magnetic fields Email: [email protected]

73 LIGHT AND MATTER SOFT CONDENSED Ruckmongathan T N PHYSICS MATTER Research Interests: liquid crystal displays, addressing, controllers Email: Reji Philip (Coordinator) Sandeep Kumar (Coordinator) Email: [email protected] Research Interests: nonlinear Research Interests: chemical optics, intense laser field synthesis of liquid crystals and Yashodhan Hatwalne interactions, laser induced their applications Research Interests: plasmas Email: [email protected] Phenomenological theory of Email: [email protected] liquid crystals, membranes and polymer crystallization Raghunathan V A Email: [email protected] Hema Ramachandran Research Interests: Amphiphilic Research Interests: quantum systems, membranes, self- computing, light propagation in assembly and phase behavior of Pramod Pullarkat random media, novel optical surfactant polyelectrolyte Research Interests: Biophysics in applications of nanomaterials complexes cell dynamics, cell cytoskeleton, Email: [email protected] Email: [email protected] transport and dynamics in axons Email: Sadiq Rangwala Arun Roy Email: [email protected] Research Interests: ultra cold Research Interests: Phase molecules, ion trapping, atoms transitions and electro-optic B K Sadashiva (INSA Senior and molecules in external fields properties of liquid crystals, Scientist) Email: [email protected] physics of nanomaterials and Research Interests: chemistry of nanocomposites. liquid crystalline materials, Email: [email protected] intelligent design and synthesis Andal Narayanan of mesogens Research Interests: quantum Email: [email protected] optics, magneto-optical traps, Pratibha R electromagnetically induced Research Interests: liquid transparency crystals, nanocomposites N V Madhusudhana (INSA Senior Email: [email protected] Email: [email protected] Scientist) Research Interests: soft condensed matter, liquid crystals Sunita Sharma (Post Doctoral Lakshminarayanan V Email: [email protected] Fellow) Research Interests: Research Interests: ultrafast and Electrochemistry of surfaces and nonlinear optics interfaces, electron transfer Soma Datta (Post Doctoral Email: [email protected] processes Fellow) Email: [email protected] Research Interests: Phase transitions and electro optics of Solomon Ivan (Post Doctoral liquid crystals. Fellow) Ranjini Bandyopadhyay Email: [email protected] Research Interests: quantum Research Interests: Copolymer- information theory, theory of surfactant interactions, drug entanglement delivery systems, non-Newtonian Email: [email protected] flows, gels, soft glasses, granular media Email: [email protected]

74 Meenal Gupta (Post Doctoral THEORETICAL PHYSICS Supurna Sinha (Research Fellow) Associate) Research Interests: physical Research interests: non- Abhishek Dhar (Coordinator) properties of liquid crystals using equilibrium statistical mechanics, different experimental Research Interests: non- soft condensed matter physics equilibrium statistical mechanics, techniques Email: [email protected] soft condensed matter physics Email: [email protected] Email: [email protected] Alok Laddha (Post Doctoral Kavitha G Fellow) Sanjib Sabhapandit Research Interests: structure Research Interests: loop and phase behavior of liquid Research Interests: statistical quantum gravity physics, extreme value statistics crystals Email: [email protected] Email: [email protected] Email: [email protected] Poonam Mehta(PostMehta Doctoral Joseph Samuel Fellow) Research Interests: general Research Interests: neutrino relativity, optics, soft condensed physics and geometric phase matter physics Email: [email protected] Email: [email protected]

Roman Sverdlovdlov(Post Doctoral Madan Rao Fellow) Research Interests: soft Research Interests: quantum condensed matter physics, gravity, causal set theory physics in biology Email: [email protected] Email: [email protected]

Ryuichi Fujitaujita(Post Doctoral B R Iyer Fellow) Research Interests: general Research Interests: gravitational relativity, gravitational waves waves, general relativity Email: [email protected] Email: [email protected]

Sumati Surya Samarth Chandra (Post Doctoral Research Interests: classical and Fellow) quantum gravity Research Interests: statistical Email: [email protected] mechanics, biophysics Email: [email protected] Madhavan Varadarajan Research Interests: classical and Abhishek Chaudhuri (Post quantum Gravity Doctoral Fellow) Email: [email protected] Note: Fellowship ended on Sept 4 2009

N Kumar (Homi Bhabha Distinguished Professor) Research Interests: randomness, dissipation, and decoherence in condensed matter Email: [email protected]

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scientific/technical staff

RADIO ASTRONOMY K S Srivani I Charles Paul [email protected] LAB V Dhamodharan P V Rishin P G Ananthasubramaniam R Durai Chelvan [email protected] [email protected] R Elumalai K Chandrashekara P S Sasi Kumar [email protected] [email protected] K O Francis M S Ezhilarasi V Gokula Chandran [email protected] LIGHT AND MATTER N Gopal PHYSICS B S Girish V K Muthu (upto 30.6.2009) [email protected] M S Meena M Mani M R Gopala Krishna [email protected] [email protected] K M Mohandas

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ P A Kamini S Sunderaj (upto 30.6.2009) [email protected] SOFT CONSENSED MATTER V Nagarajan S Kasturi [email protected] Mohammed Ishaq N Narayanaswamy [email protected] S Madhavi T Puttaswamy [email protected] N Ravi Sankar D Sunand [email protected] C Vinutha M Suresh Kumar [email protected] A R Shashidhara [email protected] V Venu H N Nagaraja [email protected] T H Shrinivasa [email protected] COMPUTERS T Prabu [email protected] H Subramonyam R Nanda Kumar, In-charge [email protected] [email protected] K B Raghavendra Rao [email protected] K N Vasudha Jacob Rajan [email protected] [email protected] A Raghunathan [email protected] D Vijayaraghavan B Sridhar [email protected] [email protected] P Sandhya [email protected] A Dhason Krishna Murthy S [email protected] [email protected] G Sarabagopalan [email protected] R Somashekar MECHANICAL GAURIBIDANUR [email protected] ENGINEERING TELESCOPE SERVICES S Sujatha H A Aswathappa [email protected] C M Ateequlla, In-charge T S Mamatha [email protected] [email protected] M Achankunju

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PhD students

ASTRONOMY AND Mamta Gulati (JAP student) Mahavir Sharma ASTROPHYSICS RESEARCH INTERESTS: Waves and RESEARCH INTERESTS: dynamics in disks cosmology and structure EMAIL: [email protected] formation, extragalactic Peeyush Prasad astronomy ADVISOR: S Sridhar RESEARCH INTERESTS: radio EMAIL: [email protected] astronomy instrumentation ADVISOR: Biman Nath [email protected] Nishant Kumar Singh (JAP ADVISOR: C R Subramanya student) RESEARCH INTERESTS: LIGHT AND MATTER Astrophysical flows PHYSICS Raju Ramakrishna Baddi EMAIL: [email protected] Research Interests: Physics of interstellar medium, ADVISOR: S Sridhar Seunghyun Lee observational and theoretical RESEARCH INTERESTS: Atom-Ion

astrophysics Kanhaiya Lal Pandey interaction ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ EMAIL: [email protected] RESEARCH INTERESTS: EMAIL: [email protected] ADVISOR: Anish Roshi cosmology and structure ADVISOR: Sadiq Ragwala formation, reionization era

Ruta Kale EMAIL: [email protected] Archana Sharma RESEARCH INTERESTS: Galaxy ADVISOR: Shiv Sethi RESEARCH INTERESTS: quantum clusters, Magnetic fields in intra- interactions with cold atoms, cluster medium Nipanjana Patra (JAP student) molecules and ions EMAIL: [email protected] RESEARCH INTERESTS: EMAIL: [email protected] ADVISOR: K S Dwarakanth Cosmology, global 21 cm, EOR ADVISOR: Sadiq Ragwala EMAIL: [email protected] Wasim Raja ADVISOR: Ravi Subramanyan Arijit Sharma RESEARCH INTERESTS: neutron RESEARCH INTERESTS: laser stars, pulsars & transients, Chandreyee Maitra (JAP cooling of atoms, cold instrumentation and signal student) molecules, optical lattices and processing BEC RESEARCH INTERESTS: X ray EMAIL: [email protected] Polarisation , polarimeter, EMAIL: [email protected] ADVISOR: A A Deshpande spectral studies of X ray binaries ADVISOR: Sadiq Rangwala EMAIL: [email protected] Yogesh Maan (JAP student) ADVISOR: Dr. Biswajit Paul Deepak Pandey RESEARCH INTERESTS: neutron RESEARCH INTERESTS: laser stars, pulsars & transients, Kshitij Thorat (JAP student) cooling of atoms, quantum instrumentation and signal computation RESEARCH INTERESTS: Radio processing Astronomy, optical astronomy, EMAIL: [email protected] EMAIL: [email protected] active galactic nucleus (AGN) ADVISOR: Hema Ramachandran ADVISOR: A A Deshpande evolution EMAIL: [email protected] ADVISOR: Ravi Subramanyan/ Lakshmi Saripalli

77 Nandan Satapathy SOFT CONDENSED D H Nagaraju RESEARCH INTERESTS: cold MATTER RESEARCH INTERESTS: atoms, BEC, optical lattices Electrochemistry of surfaces and EMAIL: [email protected] interfaces, electron transfer Alpana Nayak processes ADVISOR: Hema Ramachandran NOTE: Graduated in April 2009 EMAIL: [email protected] ADVISOR: V Lakshminarayan Ravi K

RESEARCH INTERESTS: laser Bharat Kumar cooling of atoms, trapping of Radhakrishnan A V ions, atom-ion interaction, RESEARCH INTERESTS: RESEARCH INTERESTS: molecule Electrochemistry of surfaces and amphiphilic systems, surfactants interfaces, electron transfer formation mechanisms processes EMAIL: [email protected] EMAIL: [email protected] EMAIL: [email protected] ADVISOR: V A Raghunathan ADVISOR: Sadiq Rangwala ADVISOR: V Lakshminarayan Mohammed Arif Kamal Suchand Sandeep Suchand Sandeep Bibhu Ranjan Sarangi RESEARCH INTERESTS: Model membranes RESEARCH INTERESTS: plasma RESEARCH INTERESTS: physics, intense laser matter Experimental Biophysics, EMAIL: [email protected] interactions, nonlinear optics Membrane Physics ADVISOR: V A Raghunathan EMAIL: [email protected] EMAIL: [email protected] ADVISOR: Reji Philip ADVISOR: V A Raghunathan S Radhika RESEARCH INTERESTS: liquid Jagdish Chandra Joshi Jagdish Chandra Joshi Brindaban Kundu crystals, nanocomposites RESEARCH INTERESTS: quantum RESEARCH INTERESTS: liquid EMAIL: [email protected] chemistry crystals, nanocomposites ADVISOR: R Pratibha EMAIL: [email protected] EMAIL: [email protected] ADVISOR: Sadiq Rangwala ADVISOR: R Pratibha S Madhukar RESEARCH INTERESTS: Jyothi S Jyothi S Hari Krishna Bisoyi surfactants, amphiphilic systems RESEARCH INTERESTS: quantum RESEARCH INTERESTS: chemistry EMAIL: [email protected] interactions of atoms, molecules of liquid crystals ADVISOR: V A Raghunathan and ions EMAIL: [email protected] EMAIL: [email protected] ADVISOR: Sandeep Kumar Rajib Basak ADVISOR: Sadiq Ragwala RESEARCH INTERESTS: Dynamics A Jayakumar and Rheology of Soft Glassy Tridib Ray Materials RESEARCH INTERESTS: theory of RESEARCH INTERESTS: quantum liquid crystals EMAIL: [email protected] interactions of atoms, molecules EMAIL: [email protected] ADVISOR: Ranjini and ions Bandyopadhyaya EMAIL: [email protected] ADVISOR: Yashodhan Hatwalne ADVISOR: Sadiq Ragwala

78 Debasish Saha P Suresh Kumar THEORETICAL PHYSICS RESEARCH INTERESTS: Structure RESEARCH INTERESTS: and Dynamics of Colloids, Electrochemistry of surfaces and Anirban Polley Rheology of Soft Glassy Material interfaces, electron transfer and Flow Behavior of Soft Solids processes RESEARCH INTERESTS: soft condensed matter EMAIL: [email protected] EMAIL: [email protected] EMAIL: [email protected] ADVISOR: Dr. Ranjini ADVISOR: V Lakshminarayanan Bandyopadhyay ADVISOR: Madan Rao Tripta Bhatia Anupam Kundu Renu Vishavkarma RESEARCH INTERESTS: theory of RESEARCH INTERESTS: biophysics liquid crystals RESEARCH INTERESTS: soft condensed matter and statistical EMAIL: [email protected] EMAIL: [email protected] mechanics ADVISOR: Pramod Pullarkat ADVISOR: Yashodhan Hatwalne EMAIL: [email protected] ADVISOR: Abhishek Dhar Santosh Gupta Anagha Datar RESEARCH INTERESTS: RESEARCH INTERESTS: biophysics Chandrakant Mishra (JAP surfactants, amphiphilic systems EMAIL: [email protected] student) EMAIL: [email protected] ADVISOR: Pramod Pullarkat RESEARCH INTERESTS: ADVISOR: V A Raghunathan gravitational radiation and P K Shabeeb general relativity Seshagiri Rao RESEARCH INTERESTS: rheology EMAIL: [email protected] RESEARCH INTERESTS: biophysics of soft matter systems ADVISOR: Bala Iyer EMAIL: [email protected] EMAIL: [email protected] ADVISOR: Pramod Pullarkat ADVISOR: Ranjini Bandyopadhyay Pragya Srivastava RESEARCH INTERESTS: biological P R Venkatramanan Avinash B S systems - theoretical studies of active processes in living cells. RESEARCH INTERESTS: Liquid RESEARCH INTERESTS: Crystals, Membranes Electrochemistry of surfaces and EMAIL: [email protected] EMAIL: [email protected] interfaces, electron transfer ADVISOR: Madan Rao processes ADVISOR: Yashodhan Hatwalne EMAIL: [email protected] Suchana Seth ADVISOR: V Lakshminarayan Rakesh Kumar Pandey RESEARCH INTERESTS: Non- equilibrium statistical mechanics RESEARCH INTERESTS: Electrochemistry, Material Samim Ali EMAIL: [email protected] science, Electrocatalysis RESEARCH INTERESTS: rheology ADVISOR: Abhishek Dhar EMAIL: [email protected] of soft matter systems ADVISOR: Prof. V. EMAIL: [email protected] Anjan Roy Lakshminarayanan ADVISOR: Ranjini Bandyopadhyay RESEARCH INTERESTS: statistical mechanics Satyam Kumar Gupta Swamynathan K EMAIL: [email protected] RESEARCH INTERESTS: liquid RESEARCH INTERESTS: chemistry ADVISOR: Abhishek Dhar crystal synthesis and of liquid crystals characterization EMAIL: [email protected] EMAIL: [email protected] ADVISOR: Sandeep Kumar ADVISOR: Sandeep Kumar

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Chaitra Shreepad Hegde RESEARCH INTERESTS: theoretical physics, statistical mechanics visiting scientists EMAIL: [email protected] ADVISOR: Abhishek Dhar ASTRONOMY AND ASTROPHYSICS Prasad V V P Sreekumar RESEARCH INTERESTS: theoretical Tarun Deep Saini physics, statistical mechanics Vinod Krishan EMAIL: [email protected] ADVISOR: Sanjib Sabhapandit LIGHT AND MATTER PHYSICS R Srikanth Suman Gaurab Das R Srinivasan RESEARCH INTERESTS: theoretical

physics, statistical mechanics ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ RADIO ASTRONOMY LAB EMAIL: [email protected] A Krishnan ADVISOR: Abhishek Dhar

ADJUNCT PROFESSORS Arnab Pal Arnab Pal Ramanath Cowsik RESEARCH INTERESTS: theoretical Anders Kastberg physics, statistical mechanics EMAIL: [email protected] ADVISOR: Sanjib Sabhapandit

Dibyendu Roy NOTE: Graduated in August 2009

Kripa G NOTE: Graduated in May 2009

Siddhartha Sinha (JAP student) NOTE: Graduated in July 2009

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Council

Dr. K Kasturirangan Member, Planning Commission Chairman

Prof. P K Kaw Director, Institute of Plasma Research Gandhinagar 382 428

Prof. V Radhakrishnan Member-Secretary Raman Research Institute Trust Bangalore 560 080

Dr.T Ramasami Secretary, Department of Science & Technology Ministry of Science & Technology New Delhi 110 016

Prof. Ravi Subrahmanyan Director, Raman Research Institute Bangalore 560 080 ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

Prof. O Siddiqi National Centre for Biological Sciences Tata Institute of Fundamental Research Bangalore 560 065

Mr. K P Pandian Joint Secretary & Financial Adviser Ministry of Science & Technology Government of India, New Delhi 110 016

Prof. A K Sood Physical & Mathematical Sciences Division Indian Institute of Science Bangalore 560012

FINANCE COMMITTEE

Dr. K Kasturirangan Member, Planning Commission Chairman

Mr. K P Pandian Joint Secretary & Financial Adviser Ministry of Science & Technology Government of India, New Delhi 110 016

Prof. V Radhakrishnan Member-Secretary Raman Research Institute Trust Bangalore 560 080

Prof. Ravi Subrahmanyan Director, Raman Research Institute Bangalore 560 080

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other staff

ADMINISTRATION ACCOUNTS UPKEEP K Krishnama Raju P V Subramanya Hanumantha (Admin. Officer) (Accounts Officer) Jayamma [email protected] V Raghunath K N Kawalappa K Raghunatha R Ramesh (Internal Auditor) (Dy. Admin. Officer) D Krishna [email protected] C Lakshmamma Marisa D’Silva PURCHASE T Mahadeva [email protected] S Srinivasa Murthy T Murali K Radha (upto 26.2.10) Narayana [email protected] C N Ramamurthy (In-charge) Sidde Gowda S R Ramasubramaniyan M Prema V Venkatesh [email protected] G Gayathri V Raveendran

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ [email protected] ESTATES & BUILDINGS STORES R Ganesh G B Suresh (Civil Engineer) [email protected] B Srinivasa Murthy (In-charge) R Sasidharan (Supervisor) V S Shailaja M V Subramanyam R Anantha Subba Rao [email protected] (Consultant) D G Padmashree LIBRARY S Anantha Raman [email protected] Y M Patil (Librarian) K Bhoopalan G V Indira (upto 26.2.10) Gunashekar S Geetha C Haridas GROUP SECRETARIES Girija Srinivasan K Palani (upto 31.12.09) M Rajagopal Astromony and Astrophysics Hanumappa K G Narasimhalu Vidyamani V Kiran P Savanur [email protected] T Subramaniyam Naidu M Manjunath Soft Condensed Matter (upto 30.6.09) M N Nagaraj Radhakrishna K M Ramesh Vrinda J Benegal [email protected] A Ramanna Raju Varghese (Graphic Arts) Light and Matter Physics Ranjithamma S Harini Kumari Support Staff [email protected] K Chowdasetty Theoretical Physics C Elumalai G Manjunatha [email protected] RAL Lab Mamatha Bai R [email protected]

82 SECURITY AMENITIES GAURIBIDANUR V Jayaraman (In-charge) (Guest House & Hostels) TELESCOPE B M Basavarajaiah Shivamallu Support Staff U A Earappa Mangala Singh Bheema Naik H Gangaiah Muniratna Gangaram Keshavamurthy T Naganna M Muniyappa Suresha N Narayanappa (In charge) Papanna K. Krishnappa D B Padmavathy N Raja Rao Munihobalaiah P C Prabhakar R P Ramji Naik K Pushparaj N Puttaswamy Ranoji Rao O M Ramachandra A Raju Shivarudraradhya G Ramakrishna N Seetharam Thippanna M Sannaiah Uma Venkataswamy H Vaderappa Sharadamma N R Srinath Yashodha Consultants K Balaji HORTICULTURE S Nagaraja Bylappa C N Ganapathy Govind K Kundagol Lingegowda TRANSPORT D Mahalinga V Jayaraman, In-charge Mailarappa M K Raju Kutty Marappa M Balarama D Muniraja K Mohanan S Muniraju G Prakash Rahamathulla Khan Rahamath Pasha Rangalakshmi G Raja Varalakshmi M Venkateshappa MEDICAL Consultant Paediatrician: Dr. M R Baliga Consultant Physician: Dr. B V Sanjay Rao Technician: R Shanthamma

CARPENTRY K M Lakshmanan (upto 30.6.2009) M Gopinath L Muthu

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publications

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The institute publishes the research activities carried out over the year in national and international peer-reviewed journals. Each of the four research groups at RRI finds their work published in distinguished journals that focus on their specific research area. For the Theoretical Physics group these include, but are not limited to the Physical Review, Classical and Quantum Gravity, Journal of Physics, Journal of Statistical Mechanics and Biophysics Journal. Research faculty and students from

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ the Soft Condensed Matter group have their work published in journals like Physical Review, Liquid Crystals, Journal of Physical Chemistry, Journal of Chemical Sciences, Journal of Applied Physics, European Physical Journal, Journal of Nanoscience and Nanotechnology and many more. Publications of the Light and Matter Physics group at RRI can be found in Physical Review, Journal of Nanophotonics, Optical Express and Canadian Journal of Physics. The astronomers and astrophysicists at RRI use the Physical Review, Monthly Notices of the Royal Astronomical Society, Astrophysical Journal, the Journal of Astrophysics and Astronomy and others as a means to share their work with the scientific community around the world. One hundred and sixteen papers featuring RRI members as their authors and/or co-authors were published during the year. There were 29 publications in conference proceedings and 26 (21 in journals and 5 in conference proceedings) publications are in press. Members at the institute expand and diversify their work beyond the scope of highly specialized technical and science journals by publishing books and/or articles for popular science magazines.

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other activities

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CONFERENCES

Conferences and visits to various institutions at home and abroad play a significant role in the research activities of the institute members. Such events provide opportunities for idea exchange and are often a starting point for future fruitful collaborations with other researchers from various institutions within India and abroad. Last year, faculty and students of the institute attended numerous conferences in India, China, Australia, Brazil, Israel and all over Europe. ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ In addition, lectures and invited talks were given at a variety of workshops, international programs, multinational project meetings and training programs. Members of the Institute visited colleges around the country and specially organized workshops on different science and research topics to deliver lectures, talk and presentations.

A full list of the conferences visited by each of the institute members is provided in Appendix II.

SEMINARS AND COLLOQUIA

Thursday colloquia are one of the numerous activities promoted at the Institute as a way to increase the interactions between the various research groups as well as RRI members and the invited speaker and his/her institution. Apart from covering relevant science topics, the colloquia often introduce new and interesting themes from various other disciplines.

85 open then ever before. Maintaining nationally and internationally open environment is crucial for the success of every research institution. Members at RRI recognize that and work tirelessly toward creating more opportunities for larger number of scientists, researchers and engineers to visit the institute, contribute new ideas and skills, while benefiting from the expertise of our own members. Visits at RRI can last from few days to few months and often lead to important collaborative results and/or the conception of new interesting projects.

Last year, the institute invited speakers from all Last year , there were more than 100 scholars over India, USA, Australia, Canada and Europe who visited RRI from 18 Indian and more than to deliver the Thursday colloquia. Topics varied 30 international institutions. RRI is happy to from “Cellular Journalism with DNA”, “Structure have so many friends and thanks all of them formation in the early Universe” and for making the environment in the institute so “Engineering of nanostructures” to “Global diverse, dynamic and vibrant. Indians: Negotiating identity in the software A list of all visitors, where they come from and industry” and “Gandhi, a man of the past or a when they visited RRI can be found in man of the future?”. Appendix IV. A complete list of the speakers, their lecture topics and when they visited RRI is given in Appendix III. JOURNAL CLUB

Seminars at the institute are often delivered by The first meeting of the Journal Club was held the visiting faculty and researchers. Unlike on Sept. 19th 1981 and with minor colloquia, seminars are intended to deepen the interruptions its activities have continued up to understanding and generate discussions on a very specific research theme. Usually, the topics cover the current progress of collaborative projects between RRI and the visitor’s institution, or themes of particular interest to RRI members.

A list of the visiting research faculty and researchers to RRI during the last year, is given in Appendix IV.

VISITING SCHOLARS

A high priority is given to increasing the stream of visiting scholars to the institute. In today’s high-tech world of global connectivity the academic and research community is more

86 date. The Journal Club at RRI aims at drawing the attention of the institute members to exciting and interesting papers that appear in the literature. Given the large numbers of papers published these days, it is nearly impossible for an individual to keep track of developments outside their research specialties. The Journal Club tries to partly remedy this situation by presentations of a variety of recent papers of general interest. The last Journal Club slot of the year is traditionally reserved to review the year’s having formal and informal dinners, sport Nobel Prize Award in Physics. While speakers tournaments, and a variety of cultural present their selected papers, informal programs both with invited performers or discussions, questions and demonstrations are members of RRI itself. Such activities are strongly encouraged as often they are the considered to be an integral part of the seeds of better understanding that can lead to members’ experience at the institute. better quality research. Some of the major events that took place at A list of the papers reviewed during the RRI or were organized by some of its members Journal Club meetings last year is attached to during the last year are: the annual report as Appendix V. 13 May 2009 – RRI hosted the award ceremony for the University of Sydney’s Science Foundation for Physics scholarships. OTHERS The scholarships were given to 5 high school The RRI community is involved in various other students to attend the 35th Harvey Messel activities ranging from organizing special International Science School scholarship. RRI conferences, meetings and workshops, and facilitated the selection of the Indian students inviting college students to the campus, to for this International event as part of its outreach activities, giving Indian students an opportunity to participate and showcase their talent in the International science school.

4 December 2009 – RRI was a participant in NIAS-RRI discussion meeting on “Climate Change and Sustainable Living” which was held at the National Institute of Advanced Studies (NIAS), Bangalore.

7–10 December 2009 – RRI organized and hosted the multinational Murchison Wide Field Array project meeting.

30 January 2010 – Continuing the legacy of Sir C V Raman, the institute invited Satish Kumar to deliver last year’s Gandhi Memorial Lecture. His profound life journey and his 8,000 mile peace pilgrimage (Satish Kumar walked from

87 training and experience on the analysis of data from the Fermi Gamma-ray Space Telescope.

7–19 March 2010 – RRI organized and hosted the second RRI School on Statistical Physics. This was a pedagogical school, aimed at bridging the gap between masters-level courses and topics in statistical physics at the front line of current research. It was intended for PhD students, post-doctoral fellows and India to America without any money, through interested research faculty members at the deserts, mountains, storms and snow) serve as college and university level. Courses from the inspiring examples of the power of noble area of nonlinear dynamics and chaos, physics human values. of granular matter and nonequilibrium dynamics of quantum systems were offered 8–19 February 2010 – RRI hosted the 11th during the school. COSPAR Capacity Building Workshop. The principal objective of the workshop was to Numerous other events and activities including introduce young scientists to space based a badminton tournament, in-house meetings, Gamma-ray astronomy and provide them with concerts, formal faculty farewell dinners, college visits and more continue to enrich and diversify the academic life and atmosphere at the Raman Research Institute.

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