Mark Raizen started his scientific career in theoretical particle physics in 1984 under the supervision of Steven Weinberg at the University of Texas at Austin. In 1985 he decided to move into experimental physics in the group of Jeff Kimble (now at Caltech), and completed his Ph.D. in 1989 under the joint supervision of Kimble and Weinberg. In his graduate work, Mark was instrumental in one of the first experiments that measured squeezed states of light and also observed for the first time the Vacuum Rabi splitting in the optical domain. After graduation, Mark took a postdoctoral position in the group of David Wineland at NIST, Boulder. He developed there the first linear ion trap which has become the basis for quantum information with trapped ions.
Mark was hired in 1991 as an Assistant Professor at The University of Texas at Austin, was promoted to tenure in 1996 and to full professor in 2000. He has held the Sid W. Richardson Chair in Physics for the past seven years, one of only four such chairs in the physics department.
The research program in Mark’s group utilizes laser cooling and trapping of neutral atoms to study a wide range of fundamental problems. One of the most important results was the first direct observation of Dynamical Localization, the quantum suppression of chaos. This effect was observed in an experimental realization of the Delta-Kicked Rotor, a paradigm for classical and quantum chaos. Since that first experiment, Raizen and his group have observed the transition from manifestly quantum behavior to classically chaotic evolution in a controlled setting, addressing the important issue of quantum decoherence. The next challenge was to study quantum dynamics in a regime of mixed phase space, leading to the first observation of chaos-assisted tunneling.
In other experiments, Raizen and his group investigated quantum transport of atoms in an accelerating optical lattice. They observed Wannier-Stark ladder resonances, a fundamental effect predicted for condensed matter crystals in an external electric field. They also studied the loss mechanism during the acceleration and determined that it is due to quantum tunneling. Surprisingly, for short times they found a deviation from the exponential decay law in the survival probability. This is a manifestation of a basic quantum effect predicted over forty years ago but not observed until now. This short-time deviation from exponential decay was then used to suppress or enhance the decay rate, effects known as the quantum Zeno or Anti-Zeno effects.
In recent years the focus of the experimental research has shifted towards many-body physics. Towards this goal, Raizen and his group have built up two experiments with Bose-Einstein condensates in rubidium and sodium. They have developed a unique system for the study and control of quantum statistics of atoms. The system includes a condensate in an optical box trap together with single atom detection. In a recent breakthrough, they have directly measured atomic number squeezing in a condensate and the method should produce atomic number states which will be used for the controlled study of quantum entanglement.
In the past year and a half, the Raizen group has pioneered a totally new approach to producing ultra-cold atoms by coherent slowing of supersonic beams. Using an atomic paddle they were able to produce a slow and monochromatic beam of ground state helium. In a different approach they have used pulsed magnetic fields to slow paramagnetic atoms. Together, these methods enable trapping of ultra-cold atoms that span most of the periodic table. They plan to apply this method to trapping of spin-polarized hydrogen, deuterium, and tritium for purposes of atomic spectroscopy and precision measurement of beta decay. The latter closes a circle that started with his work in particle physics, combining new approaches in atomic physics to address fundamental questions.
Bio provided by Prof. Raizen, 2007.
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