Wave Function Renormalization Effects in Resonantly Enhanced Tunneling

TL;DR

This paper investigates how wave function renormalization influences resonantly enhanced tunneling in ultra-cold atoms within an accelerated optical lattice, revealing a connection between non-exponential decay and tunneling phenomena.

Contribution

It establishes a link between wave function renormalization parameter Z and resonantly enhanced tunneling in cold atom systems.

Findings

Decay of survival probability shows step-like structure in shallow lattices.

Wave function renormalization parameter Z characterizes non-exponential decay.

Resonantly enhanced tunneling peaks at specific lattice depths and forces.

Abstract

We study the time evolution of ultra-cold atoms in an accelerated optical lattice. For a Bose- Einstein condensate with a narrow quasi-momentum distribution in a shallow optical lattice the decay of the survival probability in the ground band has a step-like structure. In this regime we establish a connection between the wave function renormalization parameter Z introduced in [Phys. Rev. Lett. 86, 2699 (2001)] to characterize non-exponential decay and the phenomenon of resonantly enhanced tunneling, where the decay rate is peaked for particular values of the lattice depth and the accelerating force.