Student-faculty research continues to be an essential part of our program. Under the leadership of Professor Wootters, our department serves as a National Science Foundation Research Experiences for Undergraduates (REU) site. This program and other grants allow us to hire several students to work with us full time on our research in the summer. During summer 1996, ten Williams students and five students from other colleges joined our faculty to work on experimental and theoretical projects. Three of those students continued their research during the academic year, completing honors theses. This coming summer (1997) we will have seven students from Williams and five from other colleges. The students meet regularly for tea and cookies, as well as for more formal talks given by faculty or students. Those students doing experimental projects take a short course on machine shop work.
The department continues to experiment with the introductory curriculum for potential majors. As currently configured, the first semester (PHYS 141) provides a foundation in mechanics and waves while the second semester (PHYS 142) seeks to broaden the students' view of physics by covering basic ideas of quantum mechanics, relativity and statistical physics. Prof. Strait has worked on both of these courses. Prof. Bolton has taken over 141 and continued to refine the design. This year Prof. Wootters revised the lecture portion of 142 while Prof. Jones and Kevin Forkey developed some new, more challenging experiments. Although there are kinks yet to be worked out, the basic approach seems to be working well, both for majors and those wanting a solid year of physics as part of a liberal arts education.
Visiting Assistant Professor Dennis Krause continued his research on the physics of open systems, systems whose dynamical behavior is modified by their environment. This work has two primary aims: (1) to characterize and understand the general properties and behavior of open systems, and (2) to search for new physics arising in open systems that may be forbidden in closed systems. In April, he gave a review of some of this work in a colloquium entitled "Exploring Quantum Electrodynamics and the Arrow of Time with a Spring and a String" at Towson State University.
During the summer of 1996, three students worked with Krause on several projects. Andy Stortz `98 and Zoë Leinhardt `98 (Carleton College) investigated the motion of a simple harmonic oscillator coupled to a string. They showed that when the string is of finite length, the oscillator behaves remarkably like a two-level atom in a microwave cavity. The goal of this project was to use the simple model to gain physical insight into cavity quantum electrodynamics. Andy continued the work during the fall and spring semesters, developing a computer program that solved the finite spring problem. The third student, Joe Reiner `97 (Rochester Institute Technology), showed how the electrostatic analog of the Faraday effect could arise in hydrogen if an interaction that violates time reversal and parity was present.
In January, Krause taught a new Winter Study course, Confronting the Mysterious. This course had two goals: (1) to describe the methods science uses to evaluate claims of new discoveries, and (2) to develop a set of mental tools (a "baloney detection kit") that one can use when confronted by claims of extra-scientific phenomena (e.g., telepathy, ESP, astrology, etc.). In addition, Krause is developing a new course, Physics 404 Elementary Particle Physics, which he will teach next spring. In this course, Krause plans to explore the grand themes (e.g., symmetry principles, effective field theories) that underlie our current understanding of the microscopic world, and show how they relate to other more macroscopic domains of physics.
In the fall of 1996, Assistant Professor Sarah Bolton joined Professor Majumder in teaching the new course Physics 109, Sound Light and Perception. She will teach this course again in the fall of 1997, in a revised format in which lectures will be integrated with hands on experiments. Bolton also taught Physics 141, Particles and Waves (enriched) and Physics 202, Waves and Optics. During the summer of 1995, Bolton worked with Sarah Dugan `97, Rob Jenks `98, and Doug Martin `97 (Pomona) in building and characterizing an ultrafast Titanium Sapphire laser system. The laser produces pulses of less than 20 femtoseconds in duration (20 x 10-15 seconds) - short enough to take "snapshots" of electron motions and molecular vibrations. This laser is being used to study dynamics of ultrafast optical systems, including nonlinear dynamics and chaos. Sarah Dugan continued this work for her senior thesis, discovering several new regimes of nonlinear dynamics in the laser. In 1997-98 these regimes will be explored both experimentally and theoretically by Rob Jenks `98 and Chris Elkinton `98.
Bolton's work on ultrafast dynamics of semiconductors was recently accepted for publication in Physical Review B. In May of 1996, she attended the Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference in Anaheim, California. She presented her work on ultrafast dynamics in semiconductors at IMRA America in September, and her work on nonlinear dynamics at Bates College in April 1997. In July 1996, Bolton organized the "Science at Williams" day for elementary school teachers participating in the MITS teacher training program at the Berkshire Museum.
Professor Stuart Crampton currently serves as the college's Provost. He taught a magnetic resonance imaging module in a new course in the department's 450 series: Topics in Atomic Physics.
Crampton continues to serve on the Board of Directors of Research Corporation and as a consultant to the Sherman Fairchild Foundation Scientific Equipment Program. He also serves on the National Academy of Sciences Board of Assessment of the Physics Programs at the National Institute of Standards and Technology and on the National Research Council's Committee on Atomic, Molecular, and Optical Sciences.
Professor Kevin Jones continued his research collaboration with a group at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD. The basic experimental technique uses lasers to cool a gas of sodium atoms to 1/1000 of a degree above absolute zero and then "photoassociates" two atoms to form a Na2 molecule. This work has lead to the first observation of "retardation" in a molecule, that is the modification of the force between two atoms due to the finite speed of light. While predicted in 1948, and observed in the interaction between macroscopic surfaces and in the force between an atom interacting with a mirror, the simple "textbook" case of two atoms had eluded observation. This same experiment also yielded a precise value (+/-0.1%) for the radiative lifetime of the sodium atom helping to settle a long-standing controversy about this quantity. Usually one thinks of atomic measurements as providing input to molecular physics, this was an interesting case where molecular spectroscopy provided a better value of an atomic parameter than could be measured by more obvious direct means. A related experiment, involving cooperation between groups at University of Connecticut and Hannover University, yield a new measurement of the dissociation energy of Na2 and demonstrated a technique that avoids the extrapolation procedure usually employed in such measurements.
Some of this work by Prof. Jones and his colleagues caught the attention of the scientific press. There was a news item in Science and one in Physics World (the European equivalent of Physics Today). His work was selected by Optics and Photonics News for inclusion in their Optics in 1996 review of major developments for the year. It was also featured in the Physics in 1996 review done by the American Physical Society. Portions of the work were presented at the meeting of the American Physical Society Division of Atomic Molecular and Optical Physics in Washington DC in April and at the Quantum Electronics and Laser Science Conference (CLEO/QUELS) in Baltimore, MD in May.
During the 1996-97 year, Assistant Professor Protik Majumder taught Physics 301, Introductory Quantum Mechanics, and Physics 132, Electromagnetism and the Physics of Matter. In addition, with Prof. Sarah Bolton, he taught a new non-majors course in the fall entitled, Sound, Light, and Perception. During the summer of 1996, Majumder supervised three students in the summer research program. The first part of the summer was spent moving the lab to its more permanent home in the ground floor of Bronfman, and installing two new optical tables for their experiments. Julie Rapoport `97 began her thesis research by designing a new vacuum system for an atomic beam apparatus. Nara Narasimhan `97 continued work with their optical system designed to detect very small optical rotation of laser light by thallium atoms. Leo Tsai `98 also joined the group, working on a variety of laboratory projects ranging from computer simulation to electronics and optical system design. Prof. Majumder continued to serve as advisor for the Society of Physics Students at Williams, and organized the department colloquium series again this year.
Professor Majumder and his thesis students are pursuing the first of a series of laser spectroscopy and polarimetry measurements of the atomic structure of thallium. A better understanding of the structure of this complex atom is essential to be able to interpret recent precise measurements of parity nonconservation in thallium in terms of fundamental physics. In this way, the experiments will contribute to "table-top" tests of elementary particle physics that can provide information as valuable as that currently derived from high-energy physics experiments. During the `97-98 year, when Prof. Majumder will be on sabbatical leave, he and new thesis student, Leo Tsai, will work towards completing a precise measurement of an electric quadrupole transition strength in thallium.
During the past year, Professor Majumder was an active reviewer for both Physical Review and Physical Review Letters. He currently has grant proposals pending at both NSF and NIST. He presented a poster entitled "Precise Measurements of Electric Quadrupole and Dipole Amplitudes in Atomic Thallium" at the April `97 meeting of the APS Division of Atomic, Molecular, and Optical Physics meeting in Washington, D.C. Majumder also served as Secretary/Treasurer of the Williams College Chapter of Sigma Xi.
Associate Professor Jefferson Strait was on sabbatical leave this year studying optical fiber lasers in his research laboratory at Williams. 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. Strait and his students pump the gain medium with 1.06 micron light and it lases at 1.55 microns, conveniently the same wavelength at which optical fiber is most transparent and therefore most suitable for telecommunications. Since the performance of the laser depends critically on the polarization of the light in the cavity, they also are investigating the polarization properties of bent optical fiber. Strait's students Ben Evans `97 and Aaron Kammerer `98 have built an automated apparatus for measuring the temperature dependence of the polarization due to bending. During the summer of 1997, Kammerer and David Cooper (Haverford College `99) are continuing these measurements and are working with the fiber laser. Their eventual goals are to produce pulses of light about 10-12 seconds in duration and to study how these pulses propagate in optical fiber.
In April, Strait gave a talk titled "Communicating at the Speed of Light" at the Williams Club in New York City. In May, he attended the Conference on Lasers and Electro-Optics in Baltimore. He also reviewed papers for Applied Physics Letters.
Professor William Wootters worked with two thesis students this year, Jennifer Drake `97 and Scott Hill `97. Both projects were in quantum information theory, a relatively new area of research stimulated largely by the 1994 discovery that a quantum computer could in principle solve certain problems exponentially faster than an ordinary computer. Jen studied various means of compressing quantum data, while Scott worked on quantifying "entanglement," a peculiarly quantum mechanical kind of correlation that will be central to the operation of a quantum computer. During the preceding summer, Wootters worked with Hill and two other students, Ray Haraguchi of Williams and Steve Furlanetto of Carleton College.
Wootters presented colloquia at a number of institutions during the year. At the University of North Carolina at Chapel Hill and at Worcester Polytechnic Institute, he gave a talk entitled "Quantum Information, Quantum Coding, and Quantum Entropy." At AT&T Bell Laboratories, Wootters spoke on "Quantum Entanglement," and at the University of Vermont he gave a talk for students from all disciplines entitled "Quantum Interference: The Garden of Forking Paths." He also participated in a workshop on quantum information theory at the University of Montreal and a workshop on quantum optics and quantum computation in Pisa, Italy, where he gave a talk, "Entanglement of a Pair of Qubits," based on his work with Scott Hill `97.
Staff Physicist and BSC Coordinator Bryce Babcock spent ten days in Australia in July 1997 with Prof. Jay Pasachoff and Tim McConnochie `98 where they observed the occultation of a star by Neptune's moon Triton on July 18. He is continuing to prepare their apparatus for the next solar eclipse which will be observed from Aruba, Netherlands Antilles. (For further details regarding both experiments, see the astronomy departmental section.) In addition to his work developing research and instructional laboratory apparatus for the sciences, he taught a reading course in the spring semester, Advanced Electronics (PHYS 456). He continues to serve on the science facilities Building Committee and maintains the Bronfman Web Site http://www.williams.edu/BSC. The site provides information about the sciences at Williams including html versions of recent copies of the Report of Science at Williams, a calendar of science activities and current information on the Science Building Project.
Emeritus Professor David Park's new book entitled The Fire Within The Eye has been published by Princeton University Press. It is a study of human efforts to understand light: what it is, what its powers are, and what it tells us about the worlds of matter and spirit.