Past Seminars Seminários Já Decorridos 2008

Cold atoms in an optical lattice: Coherent control and Quantum Chaos

By: Ben Holder
From: CFTC
At: Complexo Interdisciplinar, Anfiteatro
[2008-04-30] 11:30

The center of mass dynamics of a laser-cooled alkali atom in an optical lattice can be described using an effective Hamiltonian of a quite simple form. Under the variation of a parameter governing the lattice depth, there may appear near-degeneracies in the systems eigenvalue spectrum and, in the vicinity of these avoided crossings, the dynamics can be reduced to that of a two or three-state model system. I will describe a few such systems, including so-called Chaos-assisted tunneling and Stimulated Raman adiabatic passage, and show how they can be used to affect novel transport of trapped atoms. The simplicity of the effective Hamiltonian, which has as its classical analog a 1.5 degree-of-freedom system, also makes the optical lattice an ideal laboratory for studying the implications of quantum chaos. In particular, I will describe how the above mentioned quantum transport phenomena display signatures of the transition to chaos in the underlying classical dynamics. Conversely, increasingly chaotic classical dynamics coincides with opportunities for more efficient quantum transport.