Atomic current in optical lattices: Esaki-Tsu equation revisited

TL;DR

This paper revisits the derivation of the Esaki-Tsu equation for atomic current in optical lattices, proposing an improved relaxation term that aligns better with physical observations and experimental data.

Contribution

It introduces a more accurate relaxation term in the master equation, enhancing the theoretical modeling of atomic current in optical lattices.

Findings

Standard relaxation term predicts unphysical velocity distributions.

Proposed relaxation term better captures bosonic bath effects.

Method allows measurement of relaxation effects via velocity distribution.

Abstract

The paper discusses the master equation approach to derivation of the Esaki-Tsu equation for drift current. It is shown that the relaxation term in the master equation can be identified by measuring the velocity distribution of the carriers. We also show that the standard form of the relaxation term, used earlier to derive Esaki-Tsu equation, predicts unphysical velocity distribution and suggest a more elaborated relaxation term, which is argued to correctly capture the effect of bosonic bath in experiments on atomic current in optical lattices.