Chaotic Quantum Decay in Driven Biased Optical Lattices

Abstract

Quantum decay in an ac driven biased periodic potential modeling cold atoms in optical lattices is studied for a symmetry broken driving. For the case of fully chaotic classical dynamics the classical exponential decay is quantum mechanically suppressed for a driving frequency ωin resonance with the Bloch frequency ω_B, qω=rω_B with integers q and r. Asymptotically an algebraic decay ~t^{-γ} is observed. For r=1 the exponent γagrees with $q$ as predicted by non-Hermitian random matrix theory for q decay channels. The time dependence of the survival probability can be well described by random matrix theory. The frequency dependence of the survival probability shows pronounced resonance peaks with sub-Fourier character.

7 pages, 5 figures