Student-faculty research is 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 1995, ten Williams students and two students from other colleges joined our faculty to work on experimental and theoretical projects. Five of those students continued their research during the academic year, completing honors theses. This coming summer (1996) we will have ten 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 and another on electronics.
Since arriving at Williams in the fall, Visiting Assistant Professor Dennis Krause has been identifying novel physical effects that may arise in open systems. Examples include a permanent electric dipole moment in excited atoms, an electric analog to the Faraday effect, an imaginary component to Berry's phase, and quantum decoherence. This summer he will have three students who will be exploring the fundamental nature of classical and quantum open systems with him to understand how dissipation can lead to these phenomena. In addition, he has been working with Ephraim Fischbach at Purdue University on using many-body interactions to investigate physics beyond the Standard Model of particle physics, and on using paradoxes in probability theory to shed insight into quantum mechanics.
In April, Krause attended "Quantum Mechanics: From Microcosm to Macrocosm," a conference sponsored by SUNY at Albany that examined the foundations and consequences of quantum mechanics. As part of the Sigma Xi Math/Science event in May, he presented "Makin' Waves," an exhibition of fascinating wave phenomena in physics.
Newly arrived Assistant Professor Sarah Bolton has acquired the equipment she will use to build an ultrafast titanium sapphire laser system. This system will produce laser pulses less than 10 femtoseconds (10 x 10-15 seconds) in duration -- short enough to take "snapshots" of the fundamental motions of matter, including electron motions and molecular vibrations. During the summer of 1996, Bolton will work with Sarah Dugan `97, Rob Jenks `98 and Doug Martin (Pomona College `98) to build and characterize the laser system. They will then start work on studies of dynamics in ultrafast systems, including nonlinear behavior and chaos. Bolton has previously performed experiments exploring nonlinear dynamics of pulsed laser systems, some of which were published in September 1995 in Optics Letters. These results also appeared as a "hot topic" in the Laser and Electro-Optical Society newsletter. These measurements demonstrate that the complex interactions which allow lasers to produce very short pulses can also cause them to exhibit interesting and unexpected dynamics, and perhaps chaos.
During the summer of 1996, Bolton will be preparing two new courses. In the fall, along with Professor Majumder, she will teach a course on "Sound, Light, and Perception" for non-science majors. In addition, Bolton will conduct a winter study on the experiences of women in science.
Professor Stuart Crampton continued his cryogenic atomic hydrogen maser research with support from the National Science Foundation Program in Atomic, Molecular and Optical Physics. In addition to serving his first year as Provost, he developed and taught a new course in the department's 450 series: "Masers and Lasers."
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.
Associate Professor Kevin Jones spent the 1995-96 academic year on sabbatical at the National Institute of Standards and Technology (N.I.S.T.) in Gaithersburg, MD, investigating collisions between very cold (0.5 mK) atoms. Weak long range forces strongly influence such slowly moving atoms, so the atoms are sensitive to interactions that are masked in higher energy collisions. In particular, it is possible to photoassociate two cold atoms to form molecules at large internuclear distances. This opens up the possibility of studying purely long range states in diatomic molecules. What makes these molecular states particularly interesting is that their properties are determined almost entirely by atomic properties and thus can be calculated with unusually high precision. Working with the laser cooling group at NIST, Jones has investigated one of these purely long range states in Na2. In May he presented his results in a well-received talk at the APS Division of Atomic, Molecular, and Optical Physics meeting in Ann Arbor, Michigan. His work also will appear in an article in Europhysics Letters.
During this year, Assistant Professor Protik Majumder taught Physics 301, Introductory Quantum Mechanics, and Physics 132, Electromagnetism and the Physics of Matter. In addition he taught a new Winter Study course titled "The Science of Musical Sound." Some of the material developed in this course will be incorporated into a new non-majors course, "Sound, Light, and Perception" to be taught in the fall of 1996 with Professor Bolton. During the summer of 1995, Majumder supervised four students in the summer research program. Kyle Downey `96 and Paul Boerner `96, begin their thesis research in the atomic physics laboratory. Julie Rapoport `97 and Ruth O'Gorman `97 worked on a variety of laboratory projects of relevance to both individual research labs and the department teaching labs. Prof. Majumder also served as advisor for the newly formed Williams Chapter of the Society of Physics Students.
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. Kyle Downey's thesis describes the design and construction of apparatus to heat and control the temperature of thallium atoms in a quartz cell and to apply uniform and precisely calculable magnetic fields to these atoms. Paul Boerner's thesis outlines the design of a complete system of infrared laser, crossed polarizers, and extensive signal processing electronics which is able to detect optical rotation of laser light at the level of one microradian or less. This summer, as the lab moves to its new home in the basement, three new students will continue this work, and in particular, will construct a new thallium atomic beam apparatus designed for additional atomic measurements, as well as a system to produce frequency-doubled light at 378 nm.
During the past year, Professor Majumder reviewed papers for both Physical Review and Physical Review Letters. He attended the May meeting of the APS Division of Atomic, Molecular, and Optical Physics meeting in Ann Arbor, Michigan. He also served as Secretary/Treasurer of the Williams College Chapter of Sigma Xi and coordinated the Sigma Xi Math/Science event in May.
Associate Professor Jefferson Strait served as chair of the department this year. In addition to the routine duties of a chair, he spent a good deal of time planning for the Physics Department's part of the science facility renovation and expansion. While the department will not occupy space in the new building, we are excited about converting the present Physics and Astronomy library space into an introductory teaching laboratory and about the research laboratory space we will take over in Bronfman.
Strait continues to study optical fiber lasers and the propagation of picosecond light pulses in fibers. Previous honors students have built a laser with a cavity made entirely of optical fiber and an apparatus that can measure the duration of pulses that are too short for conventional photodetectors. Matt DeCamp `96 and Ben Evans `96 joined Strait during the summer of 1995 and continued work during the academic year on their honors thesis projects. DeCamp concentrated on improving the laser, with the eventual goal of producing mode-locked pulses of light a few picoseconds in duration. Since the performance of the laser depends critically on the polarization of the light in the cavity, Evans investigated the polarization properties of bent optical fiber. He discovered a surprisingly strong temperature dependence of the birefringence due to bending. During the summer of 1996, Aaron Kammerer `98 and Matt Partlow (St. Lawrence University `97) are following up on Ben's results.
In February, Strait presented a Williams College Faculty Lecture titled "Communicating at the Speed of Light: The Physics of Optical Fibers." He attended the Conference on Lasers and Electro-Optics in Anaheim, California.
In August 1995, Strait taught a short course in optics at Universal Instruments, Binghamton, NY. Universal builds robotic machines used to assemble electronic circuit boards. Strait's students at Universal were engineers who design the optical systems that align electronic components on circuit boards. At Williams, Strait served as the pre-engineering advisor.
Professor William Wootters has continued his research in quantum information theory, collaborating both with students at Williams and with researchers at IBM's Watson Research Center. He worked with six students during the summer of 1995, one of whom, Josh Grossman, also did a senior thesis this year. Josh's thesis showed how to translate the mathematical descriptions of certain measurements in quantum mechanics into physical realizations. Professor Wootters and his collaborators have published two papers this year in the journal Physical Review Letters. These papers are all directed towards developing the concepts needed to analyze the dynamics of information in quantum mechanical systems.
Off the Williams campus, Professor Wootters gave a colloquium entitled "Quantum Teleportation" both at Rensselaer Polytechnic Institute and at the University of Innsbruck, Austria, where he spent a week in June. He gave another talk, "Quantum Entanglement as a Quantifiable Resource," at Los Alamos National Laboratory and at the University of New Mexico, where he served as external examiner for a doctoral defense. Finally, he continued his term on the editorial board of Physical Review A.
Staff Physicist and BSC Coordinator Bryce Babcock spent two weeks during the fall semester in India where he collaborated with Professor Pasachoff of the Astronomy Department, on experiments at the total solar eclipse in Mukundgarh, October 24 (see more detailed comments in the Astronomy section.) In addition to his continuing work developing research and instructional laboratory apparatus, he taught a new reading course in the spring semester, Advanced Electronics (PHYS 456).
Emeritus Professor David Park is spending his retirement working as hard as ever. During the fall semester he taught Physics 141, our introductory course for potential physics majors. Princeton University Press has accepted for publication his most recent book, a history of optics.