PHYSICS DEPARTMENT

Many of the students who come to Williams and major in physics or astrophysics decide to continue with graduate school in physics, engineering or related subjects. Some go immediately after graduating, others take a year or two before applying. If we count all of the students applying this year, we had a total of 13 from the classes of ’03 to ’06. There was an unusually high interest this year in Aero/Astro engineering with four students being admitted to PhD programs (Cornell, Purdue, MIT and Texas). Three chose physics PhD programs (Caltech, UConn, Yale), one a biophysics PhD program (Princeton), and one a biomolecular engineering program (Cornell). In addition, one student will be entering an applied math PhD program (Cornell), one a computer science PhD program (U Washington), and one a science education PhD program (Harvard). Finally, one student will be starting a masters program in mechanical engineering (sustainable energy) at Colorado State.

Looking back at the classes of ’00 through ’03, we graduated 76 majors. Of these, 30 are in science PhD programs, 5 in non-science PhD programs, 7 in science masters programs, 3 in non-science masters programs and 2 in professional programs. This is consistent with the recent trend that about half of our majors enroll in PhD programs, mostly in science. What we hear back from these students is that they generally feel well prepared for graduate work, despite the relatively small number of physics courses they take at Williams. Most students cite our upper level tutorial courses as particularly valuable preparation for graduate work.

Associate Professor Daniel Aalberts and Evan Miller ’06 studied the abundance of RNA pseudoknots and have a paper submitted. He also studied intramolecular base stacking interactions in RNA with Rob Terchunian ’06 and microarray thermodynamics with Teng Jian Khoo ’09. Prof. Aalberts and honors thesis student Rob Cooper ’06 investigated how the cell can thermodynamically and structurally distinguish the parts of precursor mRNA which code for proteins, the parts which do not, and the junctions between.

Aalberts taught Seminar in Modern Physics (PHYS 151) under the Critical Reasoning and Analytical Skills (CRAAS) initiative and added tutorial elements to Statistical Physics (PHYS 302). Aalberts also advised the Society of Physics Students and served on the Faculty Lecture Committee. He sang with the “Flatbed Jazz Band” and participated in dance master classes.

Associate Professor Sarah Bolton had the pleasure of teaching the tutorial in Electromagnetic Theory (PHYS 405T) to twenty-four students in the fall. This fall also brought the opportunity to help fifteen current and former tutorial students as they applied to graduate programs in physics, engineering, molecular biology, and education. In the spring, she taught Electromagnetism and the Physics of Matter (PHYS 132) to 56 students, almost all of whom used the course to prepare for medical school. Outside the college, Bolton worked with the “Girls in Science” program in Sheffield, MA, to bring ideas about optics to a dozen fifth and sixth grade girls.

Bolton spent the summer of 2005 in the lab, studying fast processes in nanometer scale semiconductors with research student Creston Herold’06. This work was continued by Creston in his senior research project. In addition to her on-campus responsibilities, Bolton continued to serve as a reviewer for the National Science Foundation, Research Corporation, Physical Review, Optics Express, and Optics Communications. She also had the opportunity to learn about the physics program at Swarthmore College as a member of its visiting external review committee. In May, Bolton attended the Quantum Electronics and Laser Science Conference in Long Beach, California, where she chaired a session on ultrafast dynamics in metals. This year she will chair the program committee on “Ultrafast Dynamics” for this meeting. Bolton’s research is supported by a continuing grant from the National Science Foundation.

With Williams College Chaplain Rick Spalding, Stuart Crampton, Barclay Jermain Professor of Physics Emeritus, co-directed the North Berkshire Center for Religion and Science (NBCRS). NBCRS is funded by the Metanexus Institute as a Local Society. The purpose is to promote constructive discussions of the relationship of science and religion within the college and out in the local community. During 2005-2006, NBCRS sponsored a monthly faculty seminar and a monthly community seminar involving local clergy paired with scientists from their congregations. NBCRS also co-sponsored the January visit and talks by Harvard biologist Edward O. Wilson. Crampton serves as a consultant to the Murdock Trust, a foundation supporting science in the five northwest states, and as a consultant for the Sherman Fairchild Foundation Scientific Equipment Program. He serves as a Director and currently chairs the Board of Directors of Research Corporation, America’s oldest science-related foundation.

Professor Kevin Jones continued his active collaboration with the internationally known research group at the National Institute of Standards and Technology headed by Dr. William Phillips. Thanks to a recent sabbatical, Jones had four papers published this year in refereed journals. One was an invited review of the field of photoassociation spectroscopy that appeared in Reviews of Modern Physics. Two others appeared in The Physical Review, one as a special “rapid communication” meriting expedited publication. The final paper was published in a new European online journal called The New Journal of Physics. The editors selected this paper, on the all-optical production of a sodium Bose Condensate, for inclusion in a special collection of journal articles, “IoP Select,” judged to represent “substantial advances or significant breakthroughs, a high degree of novelty and having significant impact on future research.” The editors report that the number of downloads for the paper puts it in the top 10% of all papers recently published by the Institute of Physics.

This summer, Jones and Kristen Lemons ’08 are working at NIST on a nonlinear optics experiment that uses a novel process to generate twin beams of light that have relative intensity noise below the standard quantum limit. Specifically they hope to investigate the effect of passing one of the beams through a “slow light” medium in which light pulses propagate at extremely low speed. They are working closely with Colin McCormick ’95 who is currently a postdoc at NIST.

In January, Jones served on the Atomic, Molecular and Optical Physics funding panel for the National Science Foundation. He is also a regular reviewer for journals such as Physical Review Letters and the American Journal of Physics. In the spring, Jones taught our large non-majors course, this year entitled The Search for Rhythm and Pattern in the Universe (PHYS 100). In an effort to engage students in this large lecture course, Jones, with the able assistance of our lab instructor Kevin Forkey, instituted a series of lab exercises–some take-home and some drop-in. In the culminating lab exercise, students built a transistor circuit that controlled a “brushless DC motor.” Although the students, who almost universally self identify as “not a math/science person,” had some initial doubts about their ability to carry out the project, 98% of the 109 students in the course successfully completed the exercise. Similarly, on the theory side, the vast majority of the students rose to the challenge of tackling some demanding quantitative problems. The results from this initial offering are encouraging and we will continue to look for additional ways to make this course engaging and appropriately challenging.

During fall 2005, Prof. Tiku Majumder taught Sound, Light, and Perception (PHYS 109), and supervised one senior thesis student, David Butts ’06. In the spring, he enjoyed a one-semester sabbatical, working in the lab with David, and traveling to give several invited seminars on ongoing research. David accompanied Prof. Majumder to the May 2006 American Physical Society Division of Atomic, Molecular, and Optical Physics meeting in Knoxville, Tennessee, where they presented both a talk and poster on their work.

During the summer of 2005, Prof. Majumder supervised four students in the summer research program. Joe Kerckhoff ’05, having just graduated in June 2005, spent his third summer in the lab prior to beginning the physics Ph.D. program at Caltech in fall 2005. Joe worked with rising senior David Butts ’06 as he began his thesis research, as well as rising juniors Daniel Sussman ’07 and Margaret Pigman ’07. Postdoctoral associate, Dr. Ralph Uhl, continued to be an invaluable member of the research team, helping to supervise the students and move projects forward in the lab. In addition to this, he offered able and welcome assistance in the PHYS 301 teaching laboratory this fall. Sadly, we had to bid farewell to Ralph in December as he completed two very productive years in the lab and now will pursue a physics position in his native Germany (Berlin). With the aid of a new three-year, $230,000 NSF grant, Majumder is currently in the midst of a search for a new postdoc, who will hopefully come on board by the end of the summer.

The Majumder group continues to pursue high-precision diode laser spectroscopy of thallium in their atomic physics lab. This year, David Butts ’06 continued the development of a new system for studying a very weak transition in thallium, which necessitated a new spectroscopic method. David pushed forward on several fronts (optical system, vacuum system, electronics and signal processing, as well as Mathematica simulations) towards the realization of our new “differential phase shift” spectroscopy technique. This requires the use of an optical ring cavity interaction region, new signal-processing electronics, and a frequency-stabilized laser, all of which were successfully tested in a series of proof-of-principle experiments. The details of our new scheme to lock our diode laser to this forbidden atomic transition were published in the Review of Scientific Instruments in September 2005.

Majumder completed a rotation on the executive committee of the APS Topical Group on “Precision Measurements and Fundamental Constants” this year. Last summer, he was elected to become vice-chair (and then chair) of the Atomic Physics Gordon conference, and will be responsible for organizing the scientific program of this important meeting when it is next held in 2007 and again in 2009. The summer of 2006 promises to be a very active one in the Majumder lab, as three rising seniors (Jared Strait ’07, Owen Simpson ’07, and Toby Schneider ’07) begin their thesis work, joined by rising junior Paul Hess ’08.

David Park, Professor Emeritus of Physics, published the fourth of his series of books combining history and science: The Grand Contraption: The World as Myth, Number, and Chance (Princeton University Press). David kicked off the department’s celebration of the World Year of Physics, commemorating the centennial of Einstein’s classic 1905 publications, with a series of lectures in the spring of 2005 that reviewed Einstein’s remarkable insights concerning the photoelectric effect, Brownian motion, and the principle of relativity.  At the time he authored these, Einstein was an employee of the Swiss Patent Office in Bern. This spring, David presented a Mathematics colloquium on a probabilistic approach to the Prime Number Theorem.

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 serves as the gain medium. It lases at 1.55 µm, conveniently the same wavelength at which optical fiber is most transparent and therefore most suitable for telecommunications.

During the summer of 2005, Joseph Shoer ’06 and Toby Schneider ’07 worked with Strait using the laser as a test bed for short pulses of light propagating in the fiber. Building on a mathematical model written by Aubryn Murray ’05 describing the polarization of the light inside the fiber, Joe developed a computer model describing pulse formation and propagation throughout the entire laser. During the school year, he continued as an honors thesis student and showed how the model agrees closely with the observed operation of the laser. Now that he has graduated, Joe is off to Cornell University for graduate study in astronomical engineering.

Margaret Pigman ’07 and Krystle Barhaghi ’07 joined the group during the summer of 2006. They are working on using Aubryn’s and Joe’s model to predict the behavior of the fiber laser under a number of conditions. Margaret plans to continue this work as an honors thesis student this coming academic year.

Strait served as pre-engineering advisor and continues to serve as department webmaster. He also served the college on the Committee on Educational Policy and served the town as the chair of the Williamstown Finance Committee.

Assistant Professor David Tucker-Smith taught Particles and Waves–Enriched (PHYS 141) in the fall; a new Winter Study course, Computational Methods for Science and Engineering (PHYS 11); and Gravity (PHYS 418) and Mathematical Methods for Scientists (MATH/PHYS 210) in the spring.

During the summer of 2005, Tucker-Smith worked with Ersen Bilgin ’06 and Owen Simpson ’05 developing particle physics models with Higgs flavor multiplets, and with Utsav KC ’06 studying the phenomenology of the minimal extension of the standard model that accommodates particle dark matter. Ersen’s summer work led to a senior honors thesis, and some of his work appeared in a paper in Physics Letters, written with MIT collaborators Brian Patt and Frank Wilczek. Utsav’s summer work also led to a senior honors thesis, which investigated the prospects for detecting the annihilation products of dark matter particles captured by the sun in the minimal model. This fall, Ersen is headed to the PhD program in physics at Caltech, and Utsav will begin his PhD in aerospace engineering at UT Austin. In other activity, Tucker-Smith published a review article on little Higgs theories in Annual Reviews with Martin Schmaltz of Boston University.

In the fall, Dwight Whitaker taught Electricity and Magnetism (PHYS 201) to 22 students followed by Holography (PHYS 10) during the winter study period, taught with Kevin Forkey. In the spring term, Dwight taught Foundations of Modern Physics (PHYS 142) to a promising class of potential physics majors. In addition, Dwight served on the Faculty Compensation Committee for the first time and, in the spring, was elected to be a Faculty Associate for the new Currier Neighborhood.

A series of surface plots showing the formation of a Bose-Einstein condensate (BEC) in a cloud of rubidium-87 atoms: Atoms in the first plot can be described using classical physics. The second plot shows a cloud in which cooling has moved approximately half of the atoms into the ground state while the other half can still be described by a classical thermal distribution. The final plot is of a nearly pure BEC with almost no atoms observable in states above the ground state.

In the summer of 2005, Dwight supervised four students in his atom cooling and trapping lab. In addition to previous thesis student Justin Brown ’05, the Whitaker Lab welcomed new thesis student Paul Lindemann ’06 and rising seniors Brian Munroe ’07 and Arjun Sharma ’07. Over the summer, Brian and Arjun worked to develop a new master-slave diode laser system to more efficiently load atoms into a dipole trap produced by a single focused CO₂ laser. Paul’s thesis project was to develop a method to efficiently cool a large number of atoms within this trap through evaporation. Paul developed a system that uses a motorized telescope to squeeze atoms once they are loaded into the optical trap. Once compressed, the atoms can be quickly cooled to temperatures well below 100 nK. The Whitaker Lab is proud to report that this new evaporation scheme was successful in producing a Bose-Einstein condensate (BEC) in January of 2006. This work was presented at the annual meeting of the Division of Atomic, Molecular and Optical Physics of the American Physical Society in Knoxville, TN.

A BEC is a new state of matter that was predicted by Einstein in 1925, and first produced in a dilute atomic vapor in 1995, for which the 2001 Nobel Prize in Physics was awarded. The Whitaker Lab’s system of producing BECs, which does not use magnetic fields to hold the atoms, is more versatile than conventional techniques and could be used to trap and cool virtually any atom or molecule. This all-optical method of BEC production is the first of its kind at an all-undergraduate institution. This summer, work will continue with an eye towards making larger condensates and an improved method of temperature control of the trapped atoms. Both Arjun and Brian have elected to carry on their research in the lab as thesis students. In addition the Whitaker lab is happy to welcome aboard new physics major Nathan Cook ’08 as a summer science research student.

In addition to his atomic physics work, Dwight also continued his collaboration with Joan Edwards in the Biology Department to study rapid motion of plants. The work published by Joan and Dwight in Nature on the explosive opening of bunchberry (Cornus Canadensis) flowers continued with a paper recently submitted to The Proceedings of the Royal Society B, which models the explosive flower opening using only measured morphometric properties of the flower. This work was a collaborative effort by Joan, Dwight and former Physics student, Leon Webster ’04, who is now enrolled as a graduate student at the University of Michigan. Additionally, a study of the explosive spore discharge of Sphagnum moss was initiated with biology honors student, Clara Hard ’06. This work is ongoing and will be continued this summer with the assistance of rising physics major Shelby Kimmel ’08.

William Wootters was on sabbatical for the academic year 2005-2006. In addition to continuing his research, he used the sabbatical year to finish work on a textbook and to visit colleagues at other institutions. Wootters’ recent research has focused primarily on “discrete phase space,” a mathematical framework inspired by classical mechanics but applicable to quantum mechanical systems such as quantum computers. In the summer of 2006, Jerre He ’08 and Daniel Sussman ’07 will apply this formalism to problems in quantum information theory. In his travels this year, Wootters discussed discrete phase space and other research ideas with physicists at the University of Bristol, the Autonomous University of Barcelona, Wichita State University, and Bell Labs. He also participated in conferences at the University of Konstanz, Nicolaus Copernicus University, Perimeter Institute, Princeton University, and Colgate University.

Though he taught no courses this year, Wootters was involved in a number of activities having a pedagogical focus. He gave a public lecture and a physics colloquium as a Watkins Visiting Professor at Wichita State University, and he served as an outside examiner for the honors program at Swarthmore College. Locally, he spoke on the theory of relativity as part of a course offered by the Berkshire Institute for Lifetime Learning. The textbook mentioned above, Protecting Information: From Classical Error Correction to Quantum Cryptography, is co-authored with Williams mathematician Susan Loepp and is based on a course for advanced undergraduates that Loepp and Wootters have taught regularly in recent years.

Bryce Babcock, Staff Physicist and Coordinator of Science Facilities, continued his collaboration with Jay Pasachoff and Steven Souza on solar corona 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 serves on the Animal Care, Safety, WilliamsScene and Science Executive Committees. He also edits the Report of Science at Williams, the annual review of science activities at Williams, which is published in print and web accessible versions. (See <www.williams.edu/go/sciencecenter/center/>.)

Dr. Susan Courtney ’88, Johns Hopkins University

“Biased Competition in Working Memory and Cognitive Control: Evidence from Functional Magnetic Resonance Imaging”
Dr. A. Fenner Milton ’62, Director/U.S. Army Night Vision Laboratory

“Twenty Lessons Learned from an ‘Alternate’ Career in Physics and an Introduction to Cutting Edge Night Vision Technology”
Dr. Johnny Huckans, N.I.S.T., Gaithersburg, MD

“Optical Lattices: A Playground for Ultra-cold Atoms”
Dr. Michael Johanning, N.I.S.T., Gaithersburg, MD

“Atom Molecule Superposition and the All Optical Sodium BEC”
Dr. Carlos Vicente, University of Virginia

“The Two Dimensional Electron Gas in Tilted Magnetic Fields: Localization and Delocalization in the Second Landau Level”
Dr. Peter Nicholas ’98, University of North Carolina, Chapel Hill and Dr. Leo Tsai ’98, Harvard-Smithsonian

“Some Current Topics in Magnetic Resonance Imaging”
Dr. Benjamin Lev, California Institute of Technology

“Magnetic Microtraps for Cavity QED, BECs, and Atom Optics”
Dr. David Santiago, Stanford University

“On the Existence of Roton Excitations in Bose Einstein Condensates: Signature of Proximity to a Mott Insulating Phase”
Dr. Lily Childress, Harvard University

“Quantum Repeaters and the Nitrogen-Vacancy Center in Diamond”
Dr. Mihai Stoiciu, Williams College, Mathematics Dept.

“Spectral Theory of Random Schrodinger Operators”
Dr. M. Cristina Marchetti, Syracuse University

“Hydrodynamics and Soft Physics: From Complex Fluids to Living Cells”
Dr. Seth Major, Hamilton College

“Quantum Gravity: Is It Physics?
Dr. Michael Rust, Harvard University

“Watching Viruses Infect Cells in Real-Time”
Dr. Colin McCormick, N.I.S.T., Gaithersburg, MD

“Bullseye: Nonlinear Diffraction and Beam Reshaping in Hot Atomic Rubidium Vapor”
Dr. Nima Arkani-Hamed, Harvard University

“Fundamental Physics in 2010”

Daniel P. Aalberts

“Asymmetry and Abundance of RNA Pseudoknots”
Biology Department Colloquium

“How Not To Give a Talk”
Physics Summer Science Program
Sarah R. Bolton

“Nonlinear Microscopy”
Physics Department Summer Seminar Series, July 2005
Protik (Tiku) Majumder

“The Hanle Effect — “Level-crossing” Spectroscopy”
Physics Department Summer Seminar Series, July 2005

“Einstein in the 21^st Century”
Berkshire Institute for Lifetime Learning (BILL)
David R. Tucker-Smith

“Recent Developments in Modern Cosmology”
Berkshire Institute for Lifetime Learning (BILL)
William K. Wootters

“The Theory of Relativity”
Berkshire Institute for Lifetime Learning (BILL)

Daniel P. Aalberts

“Asymmetry in RNA Pseudoknots: Observation and Theory”
Nucleic Acids Gordon Conference, Salve Regina University, Newport, RI

“Splicing Messenger RNA”
Amherst College, Amherst, MA

“Binding Oligonucleotides: The BINDIGO Algorithm”
Columbia University, New York, NY

“Thermodynamic Modeling of Donor Splice Site Recognition in pre-mRNA”
American Physical Society March meeting in Baltimore, MD
Protik (Tiku) Majumder

“New Tools for High-precision Diode Laser Spectroscopy of Weak Atomic Transitions”
OPTEC conference, Montana State University, Bozeman, MT

“Thallium Atoms, Diode Lasers, and Tests of Fundamental Physics”
Department Colloquium, Montana State University, Bozeman, MT
Department Colloquium, Union College, Schenectady, NY
Atomic Physics Group seminar, University of Maryland, College Park, MD
Department Colloquium, Adelphi University, Garden City, NJ

“Differential Phase Shift Spectroscopy in a Thallium Atomic Beam”
Contributed talk, APS DAMOP Annual Meeting, Knoxville, TN
David R. Tucker-Smith

“A Minimally Fine-Tuned Supersymmetric Standard Model”
International Europhysics Conference on High Energy Physics (HEP-EPS 2005), Lisbon, Portugal, July 2005
Dwight L. Whitaker

“Bose-Einstein Condensate (BEC)”
Annual Meeting Div. of Atomic, Molecular and Optical Physics of the American Physical Society, Knoxville, 2006
William K. Wootters

“Discrete Phase Space Based on Finite Fields”
Workshop on Quantum Information and Quantum Logic, Perimeter Institute, Waterloo, Ontario, July 2005

“Quantum Entanglement: How a Former Paradox Is Becoming a Technology”
Einstein Centennial Symposium, Colgate University, Hamilton, NY, October 2005

“How Come Phase Space?”
Wheelerfest, Princeton University, Princeton, NJ, February 2006

“Einstein’s Spooky Action: How a Paradox of Quantum Physics Is Becoming a Technology”
Wichita State University, Wichita, KS, March 2006

“Computing with Qubits”
Wichita State University, Wichita, KS, March 2006

“Optimal Discrimination of Unentangled States”
University of Bristol, March 2006
Autonomous University of Barcelona, April 2006

“Picturing Qubits in Phase Space”
Autonomous University of Barcelona, April 2006

“Quantum Entanglement as a Resource for Communication”
Autonomous University of Barcelona, April 2006

“Phase Space for Qubits”
Bell Labs, Murray Hill, May 2006

“Geometry of Discrete Phase Space”
Quantum Entanglement and Geometry, Torun, Poland, June 2006