February 15 - 4:00pm Phys 223
(Coffee at 3:30p.m. in room 242)
Prof.Wolfgang Ketterle
Department of Physics and Research Laboratory of Electronics
Massachusetts Institute of Technology
Title: "Collective enhancement and suppression in Bose-Einstein condensates"
Abstract:
Many special properties of Bose-Einstein condensates involve the dramatic enhancement or suppression of physical processes. For example, the suppression of collisions and dissipation leads to superfluidity, and the enhancement of scattering is at the heart of matter wave amplification and the atom laser. We have studied the suppression and enhancement of elastic
collisions of impurity atoms, the suppression of dissipation for a moving object, and the suppression and enhancement of light scattering. Bosonically enhanced Rayleigh scattering was used to amplify either atoms or light in a condensate. The talk will review these experiments and discuss common roots and differences of these phenomena.
Brief Bio:
His current research is in atomic physics and laser spectroscopy, particularly in the area of laser cooling and trapping of neutral atoms with the goal of exploring new aspects of ultracold atomic matter. After the realization of Bose-Einstein condensation, his research group focuses now on the study and applications of quantum-degenerate gases and intense "laser-like" atomic beams. His earlier research was in molecular spectroscopy and combustion diagnostics.
His major accomplishments are the observation of Bose-Einstein condensation (BEC) in an atomic gas, the first realization of an atom laser, the development of important tools to manipulate and study Bose-Einstein condensates, and several seminal studies of the properties of Bose-Einstein condensates. During the early '90s, he and his collaborators developed techniques (a novel "dark" light trap, rf-induced evaporative cooling) which were crucial for the first observations of BEC both at Boulder (in rubidium, June '95) and at MIT (in sodium, Sept. '95). These observations led to a new subfield of atomic physics.
The new tools which his group developed for the study of BEC include the cloverleaf magnetic trap, dispersive imaging techniques for in situ and non-perturbative observation of BEC, the rf output coupler (which triggered the field of atom lasers), an optical trap to confine condensates, and the use of Bragg scattering as a tool for spectroscopy of a condensate. These techniques were used to explore the new physics of gaseous Bose-Einstein condensates. An interference experiment between two BECs provided the first direct evidence for the coherent nature and long-range correlations of a Bose condensate and established Bose condensates as coherent atom sources. Further important work includes studies of collective excitations in a condensate, the first measurement of the speed of sound, studies of spinor condensates, an exploration of the optical properties of a Bose-Einstein condensate, the discovery of superradiance of a condensate, a study of the formation process of the condensate, the first observation of Feshbach resonances, and the realization of phase-coherent atom amplification.
Wolfgang Ketterle is a fellow of the American physical society and of the American Academy of Arts and Sciences, and a member of the German physical society (DPG) and the Optical Society of America. His awards include a David and Lucile Packard Fellowship (1996), the Rabi Prize of the American Physical Society (1997), the Gustav-Hertz Prize of the German physical society (1997), the Discover Magazine Award for Technological Innovation (1998), the Fritz London Prize in Low Temperature Physics (1999), the Dannie-Heineman Prize of the Academy of Sciences, Gottingen, Germany (1999), and the Benjamin Franklin Medal in Physics (2000). He was selected Distinguished Traveling Lecturer of the division of laser Science of the American Physical Society (1998/99).
Wolfgang Ketterle received a diploma (equivalent to master's degree) from the Technical University of Munich (1982), and the Ph.D. in physics from the University of Munich (1986). After postdoctoral work at the Max-Planck Institute for Quantum Optics in Garching, at the University of Heidelberg and at MIT, he joined the physics faculty at MIT (1993), where he is now the John D. MacArthur professor.