PHYSICS DEPARTMENT

The Physics Department has had an exciting year. Two of our graduating seniors, Christopher Chudzicki and Scott Olesen, received awards for their excellent work at Williams. Chris was Valedictorian of his class, and has been nominated for the American Physical Society’s Apker Award for excellent undergraduate work in Physics. Scott was awarded the Herschel Smith Fellowship to support two years of graduate study at Cambridge University in Britain. Along with Physics majors Anne O’Leary and Steven Jackson, and Astrophysics major Emma Lehman, Chris and Scott started the ScientEphic Quarterly. This new college science journal is written entirely by students. They write about whatever they find most exciting, including their own research and other new developments in science. With three issues already out, the quarterly is off to a great start.

The Physics and Astrophysics majors graduated eighteen students in June. As is often the case, many of this year’s majors have decided to continue with graduate work in the sciences. Nine are starting graduate work in science or engineering this fall, and four more will apply for graduate programs to start in fall 2011. One is also starting law school, proving again that the Physics and Astrophysics majors are great preparation for many professions.

The Physics and Astronomy colloquium program had another exciting year, bringing thirteen speakers for our weekly talks. We were particularly pleased to have three accomplished alumni among the group, Dan Robb ’93, Chris Holmes ’03, and Chad Orzel ’93. We love to have our graduates back to learn where their Williams educations have taken them. Like other speakers, Dan, Chris and Chad met with current Williams students during their visits, and talked about the paths they’ve taken in their careers.

Exciting changes are afoot in the Physics Department this year! In April, Adam Falk, a theoretical particle physicist and Williams’ new President, joined the department. Though Falk won’t be teaching in 2010-11, he hopes to teach in the department soon. Chair Sarah Bolton will end her term on July 1, and begin a three-year position as Dean of the College. Kevin Jones takes up the role of department chair in the fall, and will be followed by Daniel Aalberts in spring 2011. Tiku Majumder becomes Director of the Science Center and chair of the Science Executive committee this summer.

Professor Daniel Aalberts was on leave in 2009-10, supported by NIH and NSF grants. He was awarded a $79,200 NIH supplement grant. In September, Bill Jannen ’09 joined the lab as a Scientific Programmer. Aalberts and Jannen have collaborated to develop new methods to visualize ensembles of RNA secondary structures in thermal equilibrium and to identify the barriers between these groups of states. In summer 2010, Jeff Meng ’11 and Becca Sullivan ’11 will begin their honors thesis research projects in the Aalberts lab.

Sarah Bolton continued as Chair of the Physics Department this year. She very much enjoyed teaching Introductory Mechanics (PHYS 131) to an excellent group of seventy-five students with a wide variety of interests in the fall, and Statistical Mechanics and Thermodynamics (PHYS 302) to junior and senior Physics majors in the spring.

In summer 2009, Shirish Poudyal ’10 and Anna Hurlimann ’12 worked to bring the Terahertz spectroscopy system to fruition in the Bolton lab. Terahertz radiation, which lies between infrared light and microwaves in the electromagnetic spectrum, is very useful for probing the properties of large molecules and solids. Shirish and Anna studied the ways that variations in the generating optical pulse influence the properties of the terahertz pulse it produces. Shirish continued this work in the academic year, making prototype measurements of the terahertz optical properties of fused silica in preparation for measurements on semiconductors.

In addition to her work at Williams, Bolton continued to serve as an external grants evaluator for Research Corporation and the National Science foundation, and as a reviewer for the American Journal of Physics, Optics Letters and the Physical Review. She also served as an external reviewer for the Physics Departments at Amherst (in March) and Bowdoin (in April.) In December she worked with all the eighth grade students at Mount Greylock Regional High School on a daylong program about gasses, temperature, and pressure.

Professor Kevin Jones continues his association with the internationally known research group at the National Institute of Standards and Technology (NIST) headed by Dr. William Phillips. In partnership with Dr. Paul Lett and others, he is studying the production and characterization of quantum states of light. This is a relatively new field for him and he has recently begun to publish in the area. He was very pleased to have an article accepted for publication in Physical Review Letters, one of the top journals in physics. In this paper he and his coauthors characterize the behavior of an optical amplifier that operates very close to the fundamental noise limits set by quantum mechanics. They demonstrate the use of this amplifier for manipulating one half of an entangled quantum state.

In another publication, this one in Optics Express, the rapid publication journal of the Optical Society of America, Jones and his coauthors describe their investigations into various alternative schemes for producing quantum mechanical twin beams of light using non-linear optical processes in a gas of rubidium atoms. They were able to characterize the ways in which actual laboratory implementations deviate from the idealized results predicted by simplified models. Jones served as a reviewer for the National Science Foundation, the Austrian National START program, the Physical Review, Optics Letters and the American Journal of Physics. In the spring, Jones taught our Modern Physics (PHYS 142) for freshmen course. Although the course has been in place for many years, and he had a hand early on in developing the labs, this was his first time actually teaching the course and he thoroughly enjoyed the experience.

Research in Ward Lopes’ lab continued with the themes of studying the self-assembly of organic molecules and using holographic control of light for micromanipulation. Along with professors from the departments of Chemistry, Biology, and Computer Science, Ward was awarded a $333,000 grant from the NSF to buy a pair of Atomic Force Microscopes (AFMs). These microscopes, with their ability to characterize nanoscale features on samples, have greatly aided (and enabled) research in the Lopes Lab.

Using the new AFMs, Scott Olesen ’10 investigated a common assumption that the microscopic mechanisms by which materials become more ordered depend only upon the fundamental symmetries of the material in question. Scott studied a class of organic molecules, which self-assemble to form stripes. Defects in the striped pattern are free to move when the sample is heated and they tend to annihilate in order to reduce the energy of the sample. The mechanisms by which defects in striped samples annihilate are well studied and it is believed that all striped samples behave the same way. Scott, however, observed many annihilation events, which run counter to the previously observed annihilation mechanisms. Scott was awarded High Honors from the department for his efforts. Scott’s work will be continued during the summer of 2010 and during the 2010-2011 academic year by thesis student Leah Hurwich ’11. Leah will study the statistics of the annihilation events in the same organic molecule system and will study how the number of defects changes as a function of time.

On the optical side of the lab, Joseph Skitka ’10 used the summer of 2009 and his thesis work during the 2009-2010 academic year to investigate algorithms for calculating phase-only holograms. Holographic Optical Trapping (HOT) is a method for optical micromanipulation. For various historical and practical reasons, the holograms used in HOT use only the phase degrees of freedom of the light used in optical micromanipulation. This greatly increases the difficulty and time to calculate appropriate holograms. Joe discovered and numerically tested a couple of algorithms which give improved theoretical performance in less computational time than well established algorithms used for calculating phase only holograms. Starting in the summer of 2010 and continuing into the 2010-2011 academic year, Peter Gottlieb ’11 will test and characterize how well these algorithms operate in a laboratory environment as part of his thesis work. Peter Mertz ’12 continues his work to improve methods of depositing inorganic materials from chemical solutions at the focus of a laser beam. This summer, he will extend his work to electrically characterizing the structures that he makes.

During the 2009-2010 academic year, Prof. Tiku Majumder was on a full-year sabbatical. He continued to pursue diode laser and atomic physics experiments in his research lab, teaming up with senior Anne O’Leary in the fall of 2009. He wrote and submitted a new three year NSF research proposal, which was funded this spring. This new $300,000 grant will support summer students, laboratory equipment, and the hire of a new postdoctoral research associate.

This year’s experimental work continues efforts in the Majumder lab to make very high precision measurements of atomic structure of heavy metal elements such as thallium and indium. These measurements test state-of-the-art calculations of atomic structure in these multi-electron atoms, and are useful in providing tabletop tests of fundamental physics of the sort normally associated with elementary particle theory and high-energy accelerators. In the course of the most recent work with indium, Charles Cao ’09, now at Princeton (building on work of Paul Hess ’08, now at Harvard) completed a complex spectroscopy experiment requiring the use of two lasers. Use of the first, a blue laser at 410 nm, required us to develop a new laser frequency stabilization scheme. The other laser, an infrared diode laser at 1291 nm, was then used to scan across the hyperfine spectrum of a particular state of indium. This required working not only on the laser/optical side of the experiment, but on the data acquisition and analysis side as well, investigating all manner of statistical and potential systematic errors. This work resulted in two journal publications, each with two student co-authors. Anne O’Leary ’10 began some follow-up work, extending our indium spectroscopy in a direction that will include the atomic beam apparatus. Anne, a double major in Physics and Geosciences, also completed a research project with Geoscience Prof. Mia Cook and will begin a Ph.D. program at Princeton in the latter field.

On the administrative front, beginning in the summer of 2010, Prof. Majumder will be stepping into the very large shoes of Chemistry Professor Chip Lovett as the new Director of the Science Center and Chair of the Science Executive Committee. Also this summer, he will be supervising the research work of four Williams physics students, rising senior Tony Lorenzo ’11 who is beginning his thesis work, rising juniors Joel Clemmer ’12 and Julian Hess ’12, and rising sophomore Ari Benjamin ’13. These students will be pursuing a new indium atomic beam spectroscopy experiment, as well as working on development of possible new advanced teaching laboratory experiments.

Professor Jefferson Strait and his students have built and are studying an optical fiber laser that produces pulses of light about one picosecond long. Unlike most lasers, which use mirrors to confine light to the laser cavity, an optical fiber laser uses a loop of fiber as its cavity. A section of fiber doped with erbium acts as the gain medium. It lases at 1.55 microns, conveniently the same wavelength at which optical fiber is most transparent and therefore most suitable for telecommunications. This laser functions as a test bed for short pulses of light propagating in fiber.

During the summer of 2009, Mathew Obengo ’10 and Jimi Oke ’10 worked with Strait modifying the laser and refining a model describing pulse formation in it. The polarization of light in the laser cavity plays an important role, so they installed new fiber with low inherent polarization properties. Jimi continued to work with Strait during the academic year and wrote his honors thesis on these experiments. Takuto Sato ’12 and Nathaniel Lim ’11 will join Strait’s lab during the summer of 2010 to continue this work.

During the spring semester Strait taught his new course, Energy Science and Technology (PHYS 108) for the second time. This course aimed to give majors outside the natural sciences a quantitative approach to issues in energy supply and use. After an introduction to some basic physical principles, the course covered electric power generation (fossil fuels, nuclear, photovoltaic solar cells, wind turbines), transportation (internal combustion engines, electric cars, hybrid cars, hydrogen fuel cell cars) and energy efficient building technologies. Strait plans to teach the course again next year and hopes that it will become a regular offering of the Physics Department.

Strait serves as pre-engineering advisor, department webmaster, and College Marshal, the faculty member responsible for coordinating the Convocation and Commencement ceremonies. He also has served the town for 18 years as a member of the Williamstown Finance Committee.

Frederick Strauch continued his work in superconducting quantum circuits, quantum algorithms, and other applications to quantum information processing. In summer 2009, Hai Zhou ’11 and Chris Chudzicki ’10, studied transport of energy and entanglement in quantum networks. Hai analyzed the conditions for environment assisted quantum transport for simple networks (relevant for light-harvesting in photosynthetic complexes). Chris studied parallel quantum state transfer, with potential applications to routing information in quantum computer. He extended this work to parallel entanglement distribution for his senior thesis, which received highest honors from the department. Steven Jackson ’10 returned to the (computer) lab to study disorder in quantum walks for his honors thesis, in which he established both the localization and quantum-to-classical transitions previously studied by Teng Jian Khoo ’09.

Strauch also developed a collaboration with Ray Simmonds at the National Institute of Standards and Technology in Boulder, CO (where he visited last summer) and Kurt Jacobs at the University of Massachusetts Boston to study quantum control and measurement of superconducting resonators using high-performance parallel computing. The resulting grant proposal was recently recommended for funding by the National Science Foundation. Starting in summer 2010, projects on quantum control and state transfer will be studied by Douglas Onyango ’11, Praphruetpong (Ben) Athiwaratkun ’12, Qiao Zhang ’13, and quantum walks by Samyam Rajbhandari ’11.

In his research, David Tucker-Smith has been studying how particle physics models can be tested at the Large Hadron Collider (LHC) and at experiments that search for dark matter. In summer 2009, he worked with Praphruetpong Athiwaratkun ’11 and Alex Massicotte ’10 on the collider phenomenology of supersymmetric theories, and with Marcus Freeman ’10 he studied the observational constraints on a model of dark matter. Both Alex and Marcus continued their work for their senior honors theses, and next fall they will begin PhD programs in engineering and astronomy, respectively. In other research activity Tucker-Smith wrote and submitted for publication a paper with Abhishek Kumar and Neal Weiner of NYU, on collider signatures and dark matter in supersymmetry.

In December, Tucker-Smith participated in the workshop Direct, Indirect and Collider Signals of Dark Matter at the Kavli Institute for Theoretical Physics in Santa Barbara, and in May he attended the conference Planck 2010: from the Planck Scale to the Electroweak Scale, at CERN in Geneva. These activities were supported in part by a $115,000 NSF grant awarded to Tucker-Smith in June of 2009. Tucker-Smith also refereed papers for Physics Letters B.

In fall 2009, Tucker-Smith taught Seminar in Modern Physics (PHYS 151). This course is mainly for first-year students, and offers an introduction to special relativity, quantum mechanics, and statistical physics. In the spring semester Tucker-Smith taught Mathematical Methods for Scientists (PHYS 210), and an introduction to Einstein’s general relativity, Gravity (PHYS 418).

Professor Bill Wootters has been on sabbatical this year. He spent the fall semester at Perimeter Institute in Waterloo, Ontario, where he collaborated on a research project exploring the concept of limited holism in quantum theory. While there he participated in the Institute’s ten-day celebration of their tenth anniversary: he was a panelist for Science in the Pub and for the CBC radio show Quirks and Quarks, and he appeared in a documentary, The Quantum Tamers, produced by Perimeter Institute. During the spring semester and early summer, Wootters served as a visiting professor at the Kigali Institute of Science and Technology in Rwanda, where he supervised several senior projects and helped a few students prepare for the Physics Graduate Record Exam.

In the summer he worked with Toni Aleksandrova ’11 and Chris Liguori ’10 on the theory of infinitesimal quantum measurements, and he and his students from the previous summer, Chris Chudzicki ’10 and Jimi Oke ’10, wrote a paper based on their earlier research.

Bryce Babcock, Staff Physicist and Coordinator of Science Facilities, is retiring after 36 years with the Department and the Sciences. He continued his collaboration with Jay Pasachoff on solar and planetary occultation research. (See the Astronomy News section for details.) In addition to his efforts developing research and instructional apparatus for the sciences, Babcock served on the Animal Care, Safety, and Science Executive Committees. He also edited the Report of Science at Williams, the annual review of science activities at Williams, published in print and web accessible versions. See: <http://www.williams.edu/go/sciencecenter/center/sciwmspub.html>.

[Colloquia are held jointly with the Astronomy Dept.]

Prof. Steven Strogatz, Cornell University

“The Mathematics of Collective Synchronization”
Prof. Witold Skiba, Yale University

“The Uncharted Energy Range at the Large Hadron Collider”
Prof. Kurt Jacobs, University of Massachusetts – Boston

“Putting the Quantum into Mechanics”
Prof. David Hall, Amherst College

“Tunable Interatomic Interactions 1-2-3”
Prof. Dan Robb ’93, Berry College

“Modeling the Growth of a Hexagonal Nanoparticle”
Prof. Dave Mathews, University of Rochester Medical School

“Predicting the 3D Structure and Dynamics of RNA”
Prof. Melissa Eblen-Zayas, Carleton College

“Eu-rich EuO as a Laboratory for Exploring Colossal Magnetoresistance”
Prof. Larry Hunter, Amherst College

“Searching for Preferred Directions in Space and Time”
Bill Jannen ’09 and Prof. Daniel Aalberts, Williams College, Physics Dept.

“Introducing Zfold: Somewhere over the RNAbow”
Christopher Holmes ’03, Harvard University

“Smokestack to Stomach, Modeling the Global Spread of Mercury Pollution”
Prof. Tiku Majumder, Williams College, Physics Dept.

“Heavy Metal, Cheap Lasers, and Tests of Fundamental Physics”
Prof. Lori Goldner, University of Massachusetts

“Single Molecule Biophysics in Subfemtoliter Droplets”
Prof. Chad Orzel ’93

“Counting Atoms for Astrophysics: Atom Traps, Neutrino Detectors, and Radioactive Background Measurements”

Daniel P. Aalberts

“Loopy Stabilization of RNA Loops: How Entropy Creates Order”
Williams College Chemistry Department colloquium
Sarah Bolton

“Physics of Musical Instruments” and “Real instruments and the Sound we Hear”
two-part lecture series recorded for the iLog series of the Williams College alumni office, Recorded February 1, 2010
Protik (Tiku) Majumder

“Something Old, Something New, Something Borrowed, Something Blue”
Williams College summer science talk, July 2009

Daniel P. Aalberts

“Loopy Entropy-Driven Order”
University at Albany

“Loopy Stabilization of RNA Loops: How Entropy Creates Order”
Swarthmore College

“Loopy Entropy-Driven Order”
Massachusetts Institute of Technology
Ward Lopes

“Evolution of Order in Striped Patterns”
Berry College, October 16, 2009

“Applications of Holographic Control of Light”
Physics of Living Cells Seminar, University of Illinois at Urbana-Champaign, March 19,^, 2010
Protik (Tiku) Majumder

“High Precision Indium Spectroscopy with a Blue/Violet Diode Laser”
Yale University, atomic physics group seminar, Oct. 2009

“Heavy Metal, Cheap Lasers, and Tests of Fundamental Physics”
Bates College, invited department colloquium, March 2010
Frederick Strauch

“Quantum State Transfer with Superconducting Circuits”
Physics Colloquium, University of Massachusetts – Boston, MA, February 3, 2010

“Arbitrary Control of Entanglement between Two Superconducting Resonators”
American Physical Society March Meeting, Portland, OR, March 18, 2010
Solid State & Optics Seminar, Yale University, New Haven, CT, May 27, 2010

“Imperfect Quantum Walks in Large Dimensions”
Black Forest Focus 3, Freiburg Institute of Advanced Studies, Breisach, Germany, June 5, 2010
William Wootters

“Quantum Theory as a Real-Vector-Space Theory with a Single Auxiliary Rebit”
Reconstructing Quantum Theory, Waterloo, Ontario, August 2009

“Why Does Nature Like the Square Root of Negative One?”
Perimeter Institute Colloquium, Canada, November 2009

“Entanglement and Composite Bosons”
Quantum Information Seminar, Perimeter Institute, Canada, November 2009

“Symmetric Informationally Complete Measurements: Can We Make Big Ones out of Small Ones?”
Quantum Foundations Seminar, Perimeter Institute, Canada, December 2009

“The Entanglement Cost of a Nonlocal Quantum Measurement”
Colloquium, Institute for Quantum Computing, University of Waterloo, December 2009

“Quantum Teleportation: What It Is and What It Can Do”
Physics Seminar, Kigali Institute of Science and Technology, Rwanda, Africa, June 2010