stanford university PPHYSICSHYSICS Newsletter DEPARTMENT FEBRUARY 2006

February, 2006

to major discover- Award from the University of Rome, Letter from the Chair ies. He is the recipi- recognizing outstanding achievements ent of numerous in physics, for his “important new Dear Physics alumni and friends, awards, and a directions in the understanding of the member of the mechanism of symmetry breaking and National Academy new physics at the TeV scale.” Patricia appy New Year! This year promis- of Sciences. His Burchat was one of four Stanford fac- es to bring many exciting changes main research ulty chosen for a prestigious 2005 Stanley Wojcicki H to the Physics Department. I am interest is funda- Guggenheim Fellows Award. Andrei pleased to report that Professor Phil mental light-matter interactions, and Linde has just received a Robinson Bucksbaum has joined our faculty, with especially the control of quantum Prize for Cosmology from the Univer- a joint appointment in SLAC, Physics systems using ultrafast laser fields. We sity of Newcastle upon Tyne in Eng- and Applied Physics. Prof. Bucksbaum, are very excited about this appoint- land; this is an annual international formerly of the ment, which will help invigorate our prize for important contributions in University of department and the greater physics the field of cosmology. Previous Michigan, enjoys a community. Robinson Prize recipients include Sir world-wide reputa- Martin Rees, Prof. Alan Guth and tion as one of the I am also happy to report that four Prof. Kip Thorne. In addition, David leaders in atomic, of our faculty received important Goldhaber-Gordon received the 2006 molecular, and awards. Prof. Savas Dimopoulos National Academy of Science Award optical physics received the J. J. Sakurai Prize for his for Initiatives in Research — a prize research, having outstanding work in the field of theo- awarded annually to recognize innova- pioneered new retical particle physics. Savas was also tive young scientists and to encourage Phil Bucksbaum techniques leading honored by a Caterina Tomassoni continued on page 8

Physics Alumni Reception on October 21, 2005

hanks very much to those of you who were able to attend our special physics alumni reunion reception, T held in Varian Physics on Friday, October 21, 2005, as part of the Reunion Homecoming Weekend. The Physics department reception was attended by approximately 25 physics alumni, in addition to a number of Physics faculty, staff and current students. Professors Douglas Osheroff and Giorgio Gratta were in attendance to meet with some of their former students and colleagues.

The celebratory event provided a wonderful opportunity for alumni, faculty, and staff to mix and mingle. It was very nice to catch up with former students, and we hope that you will check our website http://www.stanford.edu/dept/physics/ index.shtml for announcements of future alumni events, and plan to attend! Please email updates about your life/career to [email protected] for future newsletter articles. stanford university PHYSICS NEWSLETTER

Professor James Cronin the 2006 Robert Hofstadter Memorial Lecturer

e are pleased to announce Fellow of the American Academy of that the annual Robert Hof- Arts and Sciences. Prof. Cronin is stadter Memorial Lectures also the spokesperson emeritus and will be given this year by U.S. Principal Investigator for the James W. Cronin, Professor Pierre Auger Project. EmeritusW of Physics and Astronomy, Enrico Fermi Institute at the Univer- The Hofstadter lectures are scheduled sity of Chicago. Professor Cronin is for Monday, April 3, 2006 (an even- the recipient of numerous awards, ing public lecture at 8:00 PM) and including the 1980 Nobel Prize for Tuesday, April 4 (an afternoon col- Physics and the National Medal of loquium at 4:15 PM). Both lectures Science in 1999. He is a member of will be held at Stanford University, the National Academy of Sciences, and we hope that you will plan to James Cronin the American Physical Society, and a attend. h

EVENING PUBLIC LECTURE AFTERNOON COLLOQUIUM 8:00 pm – Monday, April 3, 2006 4:15 pm – Tuesday, April 4, 2006

COSMIC RAYS: The Pierre Auger Observatory A fascinating scientific history for Highest Energy Cosmic Rays

In 1912 it was discovered that radiation arrived on earth from The existence of cosmic rays with energies in excess of 1020 eV rep- outer space. The story of this discovery is linked with adven- resents a scientific mystery whose solution can be found, if at all, ture, false starts and scientific rivalry. We will present some only by experimentation. I will describe the Pierre Auger Observa- vignettes from this story. For years, a controversy raged as tory, now nearing completion in Malargue, Mendoza Province, to what was the nature of this radiation — charged or neu- Argentina. The observatory detects showers of particles produced tral particles. A prominent discovery was made by the French by high energy cosmic rays (protons, nuclei, perhaps photons and physicist Pierre Auger in Paris in 1938. He found among this neutrinos). Showers produced by cosmic rays of 1020 eV produce radiation particles with energies more than eight orders of about 1011 particles spread over 50 km2 on the ground. Two tech- magnitude greater than any natural or artificially produced niques are employed to observe the showers: detection of the show- radiation native to our earth. The energy of the cosmic rays er particles on the ground and detection of fluorescence light pro- observed by Auger was about 1015 eV — a macroscopic duced as the shower particles pass through the atmosphere. The energy in a microscopic particle. In 1963, a cosmic ray was observatory is spread over 3000 km2 as the fluxes of the most ener- discovered with an energy of 1020 eV, an energy of 16 joules. getic cosmic rays are very small, roughly one/km2/century above an To understand how nature produces these highest energy energy of 1020 eV. I will describe the design principles and con- cosmic rays has been my passion and the inspiration for a struction of the observatory and early results from the observatory, large observatory in Argentina in an attempt to solve the mys- which has recorded data even while partially complete. tery. In the Physics Colloquium tomorrow I will describe the observatory and some of the early results. I invite all of you The afternoon colloquium lecture will be held in our Hewlett to attend. The lecture is a bit more technical, but I believe it is quite comprehensible because of the simplicity of the Teaching Facility, 370 Serra Street. This lecture will be held detection principles. in Room 201. If you have further questions, please contact us by phone: (650) 723-4347, fax: (650) 723-1821 or email: This evening lecture will be held on campus in our [email protected]. We hope you will plan to join us for Hewlett Teaching Facility, 370 Serra Street, (Room 200). these very exciting talks.

2 stanford university PHYSICS NEWSLETTER News from KIPAC By Roger Blandford, KIPAC Director

his has been a good year for the Kavli Institute for Particle Astrophysics and Cosmology. Our two new faculty members, Tom Abel and Steve Allen, are settling in well, and the Institute T continues to grow, especially as GLAST approaches launch in 2007. There is broad interest in many, contemporary research areas, including dark energy and dark matter, black holes, neutron stars, Philip “Flip” Tanedo quasars, supernovae and gamma ray bursts. Work on designing a camera for the proposed Large Synoptic Survey Telescope has continued under Steve Kahn’s leadership and, as Romani and Sako Physics Undergraduate describe elsewhere in this newsletter, the Hobby-Eberly Telescope has been extremely successful in finding and studying supernovae. Philip Tanedo Receives continued on page 7 Marshall Scholarship

hysics undergraduate student Philip “Flip” Tanedo was selected for a prestigious Mar- P shall Scholarship. These two-year scholarships are awarded annually to at least 40 American students to study at the graduate or sometimes undergraduate level at any British institution in any field. The scholarship covers university fees, living expenses, research and travel.

Tanedo, 21, is a senior majoring in physics and mathematics. He will study mathematics at Cambridge University for his first year and spend his second year studying at the Institute for Parti- Kavli Institute for Particle Astrophysics and Cosmology, artist rendering cle Physics Phenomenology at the University of Durham. Tanedo’s course of study will focus on classes in string theory, field theory, cosmology and mathematical physics as applicable to particle physics.

“Both universities would provide a chance to col- laborate with some of the most active theoretical physicists on the other side of the Atlantic — a rare opportunity for students in the United States,” Tanedo wrote in his application. “It is my hope that my time spent at these institutions would further develop new and novel ways of looking at problems that I can apply to my research when I return to the United States to pursue a Ph.D.”

Our congratulations to Flip on this impressive Physics-Astrophysics building, under construction achievement! h 3 stanford university PHYSICS NEWSLETTER

Savas Dimopoulos Awarded the 2006 J.J. Sakurai Prize A

D avas Dimopoulos has won Howard Georgi in 1981. This the- N A

L the 2006 J. J. Sakurai Prize ory made a precise quantitative R E

E in Theoretical Physics, “for prediction, the unification of cou- P S : his creative ideas on dynamical plings, which was experimentally O T

O symmetry breaking, supersym- confirmed in 1991 by experiments H P metry, and extra spatial dimen- at CERN and SLAC, establishing sions, which have shaped theo- it as the leading theory for physics retical research on TeV-scale beyond the standard model. Its physics, thereby inspiring a wide main prediction, the doubling of range of experiments.” the elementary constituents of mat- ter in the form of supersymmetric Savas received his Ph.D. at the particles, will be tested at the large University of Chicago in 1978 hadron collider beginning in 2007. and joined the faculty at Stan- ford in 1979. He has been Savas also proposed the possible spending most of his time existence of large new dimensions searching for the theory of with Nima Arkani-Hamed and physics beyond the standard Gia Dvali in 1998. This links the model. All three of his works weakness of gravity to the pres- cited in the Sakurai prize were ence of sub-millimeter size dimen- done while Savas was at Stan- sions, presently searched for by ford. his Stanford colleagues Aharon Kapitulnik, as well as Blas Cabr- Savas’s most influential work era and Mark Kasevich, in experi- is the proposal of the supersym- ments looking for deviations from Savas Dimopoulos metric standard model with Newton’s law at short distances. In this framework, quantum grav- ity, string theory, and black holes may be experimentally investigat- ed at the large hadron collider. Pat Burchat receives 2005 Guggenheim Fellowship Most recently, Savas put forward the theory of split supersymmetry atricia Burchat was one of 186 recipients from the United States and with Nima Arkani-Hamed. This Canada to be selected for a 2005 Guggenheim Fellowship. There were theory is motivated by earlier more than 3,000 applicants for the fellowship awards, totalling about pioneering works of his Stanford P colleagues Andrei Linde, Leonard $7 million. The fellowship provides support for research and artistic creation. Guggenheim Fellows Susskind, Shamit Kachru, Renata are appointed on the basis of distinguished achieve- Kallosh and Eva Silverstein, sug- ment in the past and exceptional promise for future gesting the possible existence of accomplishment. The Fellowship has allowed Prof. an enormous number of ground Burchat to spend time working with members of states in the fundamental theory. KIPAC on the analysis of images from the Hubble This can be tested at the large Space Telescope and the development of the future hadron collider and, if confirmed, Large Synoptic Survey Telescope; both efforts have a will lend support to the idea that goal of increasing our understanding of the distribu- our universe and its laws are not tion of dark matter in the universe. h Patricia Burchat unique and that there is an enor- mous variety of universes, each with their own distinct physical laws. h 4 stanford university PHYSICS NEWSLETTER The Dawn of Neutrino Geophysics By Giorgio Gratta

eutrinos are elementary particles evolution of the Earth to its present counterparts, KamLAND has that only interact through weak state. Until now, seismic wave prop- opened the way to this new type of N interactions. Neutrinos were agation and gravitational anomalies investigation. For the time being, the recently found to have a finite, albeit have been the only tools available accuracy of these measurements is tiny, mass. One could hardly imag- to peek inside the planet. With the limited by the meager statistics (the ine neutrinos being used for any- deepest boreholes reaching only central value of the measurement is thing of practical interest, yet, in the ~12km depth, direct analysis is lim- of 19 anti-neutrinos in about two summer of 2005, the KamLAND ited to the very skin of the planet. years of data!) and by the uncertain- collaboration published what Since neutrinos are able to cross the ties from the subtraction of several amounts to the first example of planet undisturbed from the produc- backgrounds, including the one from “applied neutrino physics”. Kam- tion point to the detector, they pro- the nuclear reactors. Yet the meas- LAND was built between 1997 and vide a new and possibly very power- urement is already showing that the 2001 by a Japan — US — China ful tool. By looking at anti-neutrinos geophysical models are not com- consortium, including the Stanford with low energies, below the energy pletely off, and the Earth’s heat pro- neutrinos group that initiated the of the bulk of their reactor-produced duction is less than 60TW at 2σ American side of the collaboration. level. More data from KamLAND The main goal of the detector was to and other dedicated detectors should study neutrino oscillations; a quan- improve this measurement and con- tum mechanical phenomenon that is tribute substantially to the under- a direct consequence of the finite standing of our planet. According mass of neutrinos. By observing to a proposal discussed at a the rate of neutrinos (actually workshop jointly organized anti-neutrinos) from a distance by the particle physics and of about 200km from the earth sciences communities nuclear reactors that generated at the University of them, KamLAND provided Hawaii, a multi megaton one of the “smoking guns” for anti-neutrino detector the existence of oscillations, could be built on a floating obtaining the most precise structure and sunk at sever- mass measurement to date. But al locations in the Pacific nuclear reactors are not the only ocean, sampling the radioac- sources for the anti-neutrinos tivity contribution of different detected by KamLAND. Long lived regions. Measurements from the radioisotopes in the Earth also pro- bottom of the ocean are particularly duce anti-neutrinos in their decay. The Earth and the Anti-neutrinos. valuable, because the near absence of These isotopes — mainly uranium, The hemisphere to the left shows the modeled crust allows for a clean measurement thorium and potassium — are “pri- distribution of sources producing the of the radioactivity from the more mordial” since their half-lives are anti-neutrino signal in KamLAND. The other mysterious mantle and core. For longer than the age of the planet. more information on this topic, see hemisphere shows the modeled concentration Indeed, part (probably about half) T. Araki et al., Nature 436 (2005) of uranium and thorium in the planet. of the heat produced by the Earth 499. h is generated by the decay of those radioisotopes, so these phenomena play an important role in the under- standing of geo-dynamics and the

5 stanford university PHYSICS NEWSLETTER “The Search for Cosmic Supernova Explosions” by Roger Romani and Masao Sako

everal members of KIPAC — verse. The survey uses the SDSS lion pixels is capable of recording Roger Blandford, Steve Kahn, 2.5-meter telescope at Apache Point 200 GB of imaging data in a single S Roger Romani, Masao Sako, Observatory in New Mexico to night of observing, allowing efficient and Chen Zheng — have recently obtain repeated multi-color images of discoveries of supernova explosions joined the Sloan Digital Sky Survey II the same 300 square-degree patch of out to redshift z~0.4, or about 1/3 (SDSS-II) collaboration to participate the sky approximately every other of the way back to the big bang. in a massive search for supernova night. A unique large-format CCD (SN) explosions from the distant uni- camera array with a total of 120 mil- continued on page 7

Figures 2 and 3: SDSS images of the field around SN2005hk, a peculiar nearby SN Ia at z=0.0131 - (left) template image constructed from observations before the SN explosion Figure 1: The SDSS 2.5-meter telescope at Apache Point and (right) search image with the SN discovery. The images are approximately 1' x 1'. Observatory, which was used as the primary telescope for discovering and measuring optical light curves of the SNe.

Figure 4: The 9.2-meter Hobby-Eberly Telescope (HET) at McDonald Observatory Figure 5: Preliminary redshift distribution of the spectroscopically con- Texas used by KIPAC members to obtain spectra of high-redshift SNe. firmed SN Ia from the first campaign, with the HET contribution shaded. 6 stanford university PHYSICS NEWSLETTER

Search – from page 6 KIPAC – from page 3

The search consists of three 3-month Institute members have used a large and includes a 160 seat auditorium; it campaigns during September 1- number of other telescopes, including will be dedicated on March 17, 2006. November 30 of 2005 - 2007. Dur- Hubble Space Telescope, Chandra The Physics-Astrophysics building, ing the first season, which recently X-ray Observatory and the Very Long being constructed next to the Varian ended, the primary focus was to Baseline Array, to study the astro- Building, will contain two basements study type Ia SNe, a class of SNe that nomical sky throughout the electro- devoted principally to laboratories are associated with thermonuclear magnetic spectrum. and two floors containing offices explosions of white dwarfs that have above ground. The Hansen Experi- presumably reached the Chan- In order to accommodate all of this mental Physics Laboratory and drasekhar limit and are known to be activity, two new buildings are under KIPAC will share this building after it nearly standard candles. The cam- construction. The first of these, the is completed over the summer. We are paign was a remarkable success and a Fred Kavli Building, is nearing com- all very excited about moving into total of 126 SN Ia in the redshift pletion by the front entrance to our new quarters and hope that you interval of 0.01 < z < 0.42 (called the SLAC. The building will accommo- will come and visit us. h “redshift desert”, since other searches date over 90 people over three floors have not found many SNe in this range) were spectroscopically con- firmed during the 3-month period. This unique set of SNe will help understand and quantify the system- atics of type Ia SNe as distance indi- cators, and will provide independent constraints on dark matter, dark energy, and the expansion history of ÖÖÖÖÖÖ the universe. Interestingly, the redshift range of the SDSS-II SNe search cov- ers most of the period where recent 2005 Student Awards work suggests that dark energy is the dominant constituent of the cosmos. number of student awards were announced at our Physics/Applied A Physics Commencement ceremony last June. ANDREA BURBANK Stanford’s partnership in the 9.2- received the David Levine Award, presented to the outstanding Junior meter Hobby-Eberly Telescope (HET) physics major. TESS WILLIAMS received the Jeffrey Willick Memorial has allowed KIPAC members to fol- Award, given to the outstanding physics student in the field of astrono- low-up and obtain optical spectra of my. The Paul Kirkpatrick Award, given to outstanding physics teaching ~50 high-redshift SN Ia, which make assistants, were given to DAVID STARR and WELLS WULSIN. The first up a large chunk of the “distant” recipient of the Arthur B. Walker Memorial Award, to promote the sample most useful for cosmological greater inclusion of ethnic minorities and women in the sciences at studies. The KIPAC group has also Stanford University, was RICHARD FOSTER. targeted different types of SNe including the peculiar Ib/c hypernova The Firestone Award for excellence in Undergraduate Research was that are believed to be associated presented to ADAM SCIAMBI. with some gamma-ray bursts and other rare types of SNe that are poor- ly sampled in other surveys. Detailed analysis of the optical light curves and spectra are in progress. h

7 Letter – from page 1 research likely to lead toward new Award of Merit. This award origi- Gratta, about their latest work. capabilities for human benefit. Gold- nated in the School of Humanities & We also have news to report on the haber-Gordon was chosen “for his Sciences in 1999 to acknowledge the newly constructed Fred Kavli Build- fundamental studies of electron corre- important role staff play in the suc- ing at SLAC and the Physics– lations in mesoscopic structures.” cess of the School and the University Astrophysics Building going in next Congratulations to these faculty on and to recognize their significant door to Varian Physics, and sched- their impressive achievements! contributions. Karlheinz joined our uled for completion this coming department in 1989, and took over summer. Both of these new facilities Several of our Physics undergraduate as Machine Shop foreman when will create tremendous new opportu- students were also recognized for Wolfgang Jung retired in 1997. nities for research, and we hope you their excellence with prestigious He has done an exceptional job of will stop by to see them when they awards. Physics undergraduate Philip overseeing our machine shop, and are completed later this year. (“Flip”) Tanedo was selected as one we are pleased that his efforts were of 43 nationwide recipients of a recognized with this award. We look forward to this year’s Marshall Scholarship. Also, Jared Robert Hofstadter Memorial lectures, Kaplan received the Hoefer Prize for Our department currently has two which will be given by Prof. James his excellence in Undergraduate junior faculty searches underway: Cronin, Emeritus Professor of Writing in the Sciences. Finally, Professor Roger Blandford is leading Physics and Astronomy of the Enrico Yanwei Jang was selected to receive a search for a theoretical astrophysi- Fermi Institute at the University an Outstanding Student Paper cist, which will be a joint appoint- of Chicago. Professor Cronin was Award from the Solar Physics Section ment with SLAC, and Professor Mark the recipient of the Nobel Prize for of the American Geophysical Union. Kasevich is leading a search in the Physics in 1980 and the National In addition, a number of our Physics field of experimental atomic, molecu- Medal of Science in 1999. The lec- students were recognized with lar and optical physics. We look tures will be held at Stanford Univer- departmental awards. We are very forward to bringing in new faculty sity on April 3 and 4, 2006 in the proud of the outstanding work done in both of those important fields. Hewlett Teaching Center, (Rooms by these students. 200 and 201, respectively). Some exciting research updates are One of our excellent Physics staff reported in this year’s newsletter — A diverse new group of 27 students members, Karlheinz Merkle, was please see articles by Roger Romani entered our Ph.D. program in 2005. also honored last year with a Dean’s and Masao Sako, and by Giorgio The incoming graduate students include 6 women and 13 foreign students. Five of our new graduate A C

, students have NSF Fellowships, five K R

A have Stanford Graduate Fellowships,

NON-PROFIT ORG. P

O two have Stanford Humanities and

U.S. POSTAGE L N

PAID E Sciences Fellowships and two have M

PALO ALTO, CA ,

O NDSEG Fellowships. We are very I

PERMIT NO. 28 D U pleased to welcome these bright new T S

S students to our department. C I H P

DEPARTMENT OF PHYSICS A R I wish to thank all of you who have Stanford University G S

K made donations to the Physics Stanford, CA 94305-4060 R O Department this past year. Your con- W C

A tributions have created many oppor- M

— tunities and events for our students N

A and for the larger physics community. E L C

c On behalf of everyone in the depart- M

A ment, I thank you again for your N N

A continued support and interest. O J : N G I With best wishes, S E D

Stanley Wojcicki Chair and Professor of Physics 8