Joint Quantum ψ Institute News for September 2009

A Summer of Outreach: A New JQI Fellow and a Distinguished Visitor Students from Middle School This month JQI welcomes two arrivals international standard for the duration of who bring additional strength and depth the second, rely on the natural frequency to College, to the Institute’s inventory of talent. at which cesium atoms oscillate between High-school two quantum conditions: a ground state Teachers and One is the newest JQI Fellow, Gretchen and an excited state. At present, the sec- REU Days Campbell, who will be a staff physicist at ond is defined as the time it takes a cesi- pages 3-5 the National Institute of Standards and um-133 atom to complete 9,192,631,770 Technology (NIST) starting September cycles between these states. That fre- 15. She received her quency falls into the Hacking the Ph.D from MIT, where microwave range of Quantum she worked in Wolf- the electromagnetic At DEFCON gang Ketterle’s and spectrum. And More: Dave Prichard’s lab and Entangled studied rubidium Bose- The best existing States Einstein condensates in cesium clocks, such optical lattices. as NIST’s F-1, have an page 6 accuracy of a few parts Most recently, Campbell in 10 quadrillion (1016), Upcoming was at JILA, a partner- but that is not suf- Workshop: ship between NIST ficiently exact for the and the University of increasingly precise Ultracold Colorado, where she demands of 21st-cen- was a research associ- tury science and tech- Group II ate in the Jun Ye group. JQI Fellow Gretchen Campbell nology. So researchers Atoms Among other pursuits, are exploring numer- Sept. 17-19 she was engaged in the effort to develop ous alternatives for higher accuracy. University of a strontium optical lattice clock -- and in Maryland the construction of a novel experimental One very promising idea is to use an for details, see apparatus that is used to explore elec- atomic transition that occurs about tronic transitions in strontium atoms. The a hundred thousand times faster -- a jqi.umd.edu/ frequency of such transitions is the fun- frequency in the optical range of EM workshop.html damental basis of modern timekeeping. radiation. Among the optimal candidate atoms is strontium. The world’s master clocks, as well as the continued on page 2 Campbell and Carmichael from p. 1

At JQI, Campbell will continue research, begun in encountered in according to a scat- the Ye group, into using an array of strontium atoms tering scenario, in which the inputs are classical fields confined in an optical lattice -- a sort of grid pat- (external fields) and the outputs are classical stochas- tern formed by the intersection of two or more laser tic processes that model the scattered fields after beams -- as a platform for quantum simulations of detection (after their measurement). many-body physics problems and as a potential clock mechanism. “The mapping from inputs to outputs is provided by a quantum stochastic process that is set up to ac- One extremely difficult aspect of this work involves count for a particular measurement strategy (e.g., exploiting a transition, artificially induced by numer- photon counting, homodyne/heterodyne detection, ous lasers acting in concert, that appears to be very etc.). Both the formal theory and its applications are stable. Creating, controlling and measuring that under study. Recent work includes the development transition require exquisitely delicate manipulation of of a novel measurement scheme to correlate the nuclear spin states using lasers and related apparatus. quadrature amplitudes of an electromagnetic field, applications of this scheme in In addition, Campbell will continue cavity quantum electrodynamics, the investigations begun at NIST by and the modelling of multimode departing JQI Fellow Kris Helmer- aspects of collective radiative son into the behavior of Bose-Ein- phenomena (super-radiance). stein condensates in toroid (do- nut-shaped) configurations. That Entanglement and Correlation in arrangement has advantages for Composite Systems certain kinds of study. For example, an ordinary BEC has a substantial “Quantum optics has traditionally density gradient, thinning out from concerned itself with uniquely the center to the edges. A toroidal quantum mechanical aspects of BEC has a much more uniform den- optical phenomena (e.g., photon sity. In addition, it provides a closed antibunching and squeezing, loop in which atoms can move or violations of Bell inequalities). forces can propagate, allowing a Attention in recent years has wide range of effects. been focused on applications of these quantum features of light The Kiwi Connection to novel schemes for processing information (so-called quantum The second arrival this month is information science). Entangled Professor Howard Carmichael of the states are central to the proposed (New Zea- information processing proto- land) Physics Department. Carmi- Visiting Professor Howard Carmichael cols. chael, an expert in cavity quantum electrodynamics and a Fellow of both the American “Current work is directed towards understanding Physical Society and of America, entangled states, and the contextual correlations they holds the Chair in Theoretical Physics. He is describe, in the broadest sense, i.e.,we are concerned spending a sabbatical year at JQI, where he will work with the physics of composite quantum systems in with many Fellows including Luis Orozco, whom Car- general. Specific interests include measures of en- michael met years ago when both were at the Univer- tanglement for open systems, and schemes for the sity of Texas at Austin. generation and manipulation of this entanglement. Continuous variable entanglement is of particular His current research is concentrated in two areas, interest. It has been suggested by others that this which he describes as follows: form of entanglement can be accounted for within stochastic electrodynamics. The suggestion is being Quantum Trajectory Theory assessed. A quantum trajectory theory of continuous variable teleportation is being developed for compar- “Quantum trajectory theory treats the open systems ison with the stochastic electrodynamics proposal.” 2 Summer Outreach 1: H.S. Teachers

Physics in Focus: On June 26, 2009, JQI’s Physics Frontier Center conducted a day-long workshop on optics in the classroom for local-area high school physics teachers, using instructional materials from the Optical Society of America. The first half of the event was devoted to demonstrations and discussion of techniques to illustrate optical phenomena. The second half involved a tour of several JQI laboratories to see some of the ways in which quantum optics is employed in ongoing research.

Clockwise from left: PFC Co-Director Luis Orozco works with Faiz Mohideen of Largo (MD) High School. PFC Co-Director Bill Phillips with Mohideen and Sarah Wendel of Parkdale High School (Riverdale, MD). Postdoc Steve Olmschenk explains an ex- periment to Wendel and Herb Edelstein of Richard Montgomery High School (Rockville, MD).

Above left: Wendel and Sederik Rice, of Bowie (MD) High School experiment with laser demonstrations for classroom use. Above right: JQI Co-Director Steve Rolston takes questions after a presentation on techniques and materials for teaching optics. Other participating teachers were: Christopher Hahn of Linganore High School (Ijamsville, MD); Jasper Layne of Largo (MD) High School; and Yau-Jong Twu, Eleanor Roosevelt High School (Greenbelt, MD).

3 Summer Outreach 2: REU Projects

2009 Summer Research Experience for Inter- national Undergraduates: Three undergradu- ate students spent ten weeks working with JQI researchers this summer.

Two were from Mexico -- Jorge Gomez (Uni- versidad de Guadalajara) and Diego Quiñones (Universidad Autónoma de San Luis Potosí). They were selected by the division of Quantum Information of Sociedad Mexicana de Fisica (Mexican Physical Society) after a national com- petition and worked in the group of JQI Fellow Luis Orozco, shown in top and bottom photos.

The third student -- Douglas Onyago, originally from Kenya -- is an undergraduate at Williams College in Massachusetts. He contacted JQI after learning of opportunities at the Annual Meeting of the National Society of Black Physi- cists and the National Society of Hispanic Physi- cists in Nashville, TN where JQI and its Physics Frontier Center had a booth. Onyago (at right in center photo) worked in the group of JQI Fel- low Trey Porto (at left in center photo).

Gomez (center in bottom photo) worked with JQI graduate student Dong Sheng (left in photo) on a “Magnetic field sensor and feed- back system for precise spectroscopy in an atom trap”.

Quiñones (at right in top photo) worked with JQI researcher Jonathan Hood (center of photo) on “Analysis of a Microwave Cavity and Antenna for driving a Parity Violating Transition”. Onyago worked with JQI student Creston Herold (not shown) on “Atomic beam collimators for Rb/Yb experiment.”

Their stay was supported by JQI, which thanks the REU MRSEC site at UMD for its hospitality in facilitating the students’ stay and making them part of the group.

All photos were taken at the final poster ses- sion for the REU MRSEC in August 2009.

Photos courtesy of Julie Callis/MRSEC 4 Summer Outreach 3: H.S. Students

Getting the Point: This summer, the Chris Monroe group added two high-school seniors to its lab team: Grace Young and Jennifer Wang. Their job was to test a “parabolic dish” trap in which individual 5-micron hol- low polystyrene spheres are confined and irradiated by laser light. The spheres serve as a point source, scat- tering light in all directions. When a sphere is placed at the focus of the dish, more than half its light emerges vertically and can be collimated and routed to a fiber.

Eventually, the group will use the trap configura- tion to hold a single atom, thereby achiev- ing very high collec- tion efficiency of single Above: Students Grace Young (left) of The Potomac photons. The arrange- School and Jennifer Wang of Montgomery Blair ment can then be put High School manipulate the trap. to use in other experi- ments. In particular, the Right: A minuscule polystyrene sphere scatters red group may replace the laser light from its position in the trap. dust particle with a tiny chunk of diamond dusk Below left: Photons scatter at all angles from the containing a nitrogen- spheres, but the parabolic disk reflects and redirects vacancy (NV) point the majority of the photons, which exit in a verti- defect. Such defects act cal direction. This makes it possible to dramatically somewhat like indi- improve the collection efficiency of the apparatus. vidual atoms, emitting single photons and per- Below right: The Monroe group often meets at mitting storage of spin Ben’s Chili Bowl, the legendary eatery on U Street in qubits. NVs are “dirtier” the District of Columbia. Young and Wang are in the sources than individual atoms, but are considerably front row, second and third from the right. cleaner than most other solid-state systems. And they can operate at room temperature in air.

sphere point source

5 Recent Publications

“Number fluctuations and en- ergy dissipation in sodium spinor condensates,” Y. Liu, E. Gomez, S. Maxwell, L. Turner, E. Tiesinga, and P. Lett, Phys. Rev. Lett. 102, 225301 (2009)

“Collisional cooling of ultracold- Stanescu, V. Galitski, J. Y. Vaishnav, Fluids (http://vjaqf.aip.org/aqf ). atom ensembles using Feshbach C. W. Clark, and S. Das Sarma, Phys. VJAQF is the sixth and latest in the resonances,” L. Mathey, Eite Ties- Rev. A 79, 053639 (2009) series of Virtual Journals co-pub- inga, Paul S. Julienne, and Charles lished by the American Physical W. Clark, Phys. Rev. A 80, 030702(R) “Blackbody-radiation shift in a Society and the American Institute (2009) 88Sr+ ion optical frequency stan- of Physics. The four papers are: dard,” Dansha Jiang, Bindiya Arora, “Low-noise amplification of a con- Marianna S. Safronova and Charles “Photon burst detection of single tinuous variable quantum state,” W. Clark, J. Phys. B: At. Mol. Opt. atoms in an optical cavity,” R. C. Pooser, A. M. Marino, V. Boyer, Phys. 42, 154020 (2009) M. L. Terraciano, R. Olson Knell, D. K. Jones and P. Lett, Phys. Rev. Lett. G. Norris, J. Jing, A. Fernández & L. 103, 010501 (2009) Papers Accepted A. Orozco, Nature Physics 5, 480 - 484 (2009) “Quantum and classical dynamics of a Bose-Einstein condensate in a “Rapid production of 87Rb Bose- large-period optical lattice,” J.H. Einstein condensates in a com- Huckans, I.B. Spielman, B. La- bined magnetic and optical “Precision Measurement of the burthe Tolra, et al. , accepted at potential,” Y.-J. Lin, A. R. Perry, R. Lifetime of the P_1/2 level of Yb+,” Physical Review A. L. Compton, I. B. Spielman, and J. S. Olmschenk, D. Hayes, D. N. Mat- V. Porto, Phys. Rev. A 79, 063631 sukevich, P. Maunz, D. L. Moehring, “Frequency and temperature (2009) K. C. Younge, C. Monroe, Phys. Rev. dependence of the anomalous A 80, 022502 (2009) ac Hall conductivity in a chiral “Number Fluctuations and Energy p_x+ip_y superconductor with Dissipation in Sodium Spinor “Large Scale Quantum Computa- impurities,” Roman M. Lutchyn, Condensates,” Y. Liu, E. Gomez, S. tion in an Anharmonic Linear Ion Pavel Nagornykh, and Victor M. E. Maxwell, L. D. Turner, E. Tiesinga, Trap,” G.-D. Lin, S.-L. Zhu, R. Islam, Yakovenko, accepted at Physical and P. D. Lett, Phys. Rev. Lett. 102, K. Kim, M.-S. Chang, S. Korenblit, C. Review B and selected as an Edi- 225301 (2009) Monroe, and L.-M. Duan, Europhys- tors’ Suggestion. ics Letters 86, 60004 (2009) “Raman processes and effective JQI in VJAQF: Four JQI papers are gauge potentials,” I.B. Spielman, “Counterflow and paired super- included in the first issue of the Phys. Rev. A 79, 063613 (2009) fluidity in one-dimensional Bose Virtual Journal of Atomic Quantum mixtures in optical lattices,” A. Hu, L. Mathey, I. Danshita, E. Tiesinga, C.J. Williams, and C.W. Clark, Phys. Rev. A 80, 023619 (2009)

“Topological insulators and met- als in atomic optical lattices,” T. D.

6 Entangled States: Way Out West

Hack the Quantum

“Hack the Quantum” is the title of the presentation staged at this year’s DEFCON hackers’ convention in Las Vegas, July 30-Aug. 2, by researchers from JQI and the Centre for Quantum Technologies, National University of Singapore (NUS). The description: “With a hands-on Bell-o-meter for entangled photons you can convince yourself that there are quantum effects beyond classical physics: a real qubit is offered to the participant who achieves the strongest violation of a Bell inequality. We also present a fresh attack that breaks many current quantum crypto systems, and demonstrate a photon-based quantum random number generator.”

Photo captions

Above, left to right: Alan Mink (JQI), Jemellie Galang (JQI), Ilya Gerhardt (NUS), Joshua Bienfang (JQI), Christina Brown (JQI) and Alessandro Restelli (JQI). Not shown: JQI Fellow Charles Clark.

At right: Correlated photons as seen with the naked eye by visitors to the JQI/NUS live demonstration of quantum random number generation, Bell violation and quantum hacking. Here, parametric down-conversion annihilates violet photons from a salvaged HD- DVD diode (central spot), resulting in correlated photons emitted on opposing sides of the rings above. Image: Matthew Stits

7 Entangled States: Going Places

Arrivals: NRC Postdoctoral Re- search Associate Amy Cassidy has joined NIST. She is seen in the photo at left, between JQI Fellow Paul Julienne and another NRC Postdoc- toral Research Associate, Ludwig Mathey, in the NIST dining hall on August 20, 2009.

Former Monroe group member Steve Olmschenk has joined the Laser Cooling and Trapping Group at NIST, where he will work with JQI Fellows Bill Phillips, Paul Lett, Trey Porto and Ian Spielman.

Emily Edwards is now a postdoc in the Monroe group, which has also added two new graduate students: David Hucul and Crystal Senko.

Departures: Former JQI/NIST postdoc Yingmei Liu has taken a faculty position at Oklahoma State University Edwards Maunz and Raphael Pooser, also a NIST postdoc, took a fel- Liu lowship at Oak Ridge National Lab.

Former Monroe group Research Scientist Peter Maunz has taken a Research Scientist position at Duke Univer- sity, and Ming-Shien Chang is joining the faculty at the Academica Sinica, Taipei, Taiwan. Chang Olmschenk Pooser

At left:

Hans Peter Büchler of the University of Stuttgart and JQI Fellows Ian Spielman and Charles Clark confer at the Work- shop on Quantum Gauge Theories and Ultracold Atoms, Sant Benet, Spain, September 3, 2009

8 Entangled States, continued

Macroscopic Phase Transition: The DARPA Optical Lattice Emulator Ian Spielman program at JQI has advanced to Phase II. JQI fellows Chris Monroe, Trey Porto, Ian Spielman and Sankar Das Sarma continue their work on the quantum simulation of materials and intractable systems using atoms and ions controlled by optical lattices.

The Phase II program, funded at approximately $3 million per year under PI Monroe, includes 16 PIs at 10 institutes. Work at JQI will use trapped ions to simulate intractable models of quantum magnetism, study atomic mixtures in optical lattices, implement a simulation of fractional quantum statistics, and advance the theory of topological quantum manipulations that emerge in such systems.

Upcoming Meeting: The kick-off meeting for “Quantum-Optical Circuits of Hybrid Quantum Memories,” the newly announced project funded by the Department of De- fense’s Multidisciplinary University Research Initiative, will be held on October 1 and 2 at the University of Maryland’s Kim Engi- neering Building, Room 1105. This MURI is led by Chris Monroe, with JQI co-PIs Edo Waks and Jake Taylor.

JQI is a joint venture of the University of Maryland and the National Institute of Standards and Technology, with support from the Laboratory for Physical Sciences.

Joint Quantum Institute CSS (Bldg. 224) Room 2207 University of Maryland College Park, MD 20742 E-mail: [email protected]