Signal of Bose condensation in an optical lattice at finite temperature

TL;DR

This paper proposes that the bimodal distribution in the momentum space density profile within the first Brillouin zone serves as a clear experimental indicator of Bose condensation in cold atoms in optical lattices at finite temperature.

Contribution

It introduces a new method to detect Bose condensation using momentum space density profiles instead of traditional interference pattern visibility.

Findings

Momentum space bimodal distribution signals Bose condensation.

Calculated atomic momentum distribution changes across the phase transition.

Method accounts for trapping potential and atomic interactions.

Abstract

We discuss the experimental signal for the Bose condensation of cold atoms in an optical lattice at finite temperature. Instead of using the visibility of the interference pattern via the time-of-flight imaging, we show that the momentum space density profile in the first Brillouin zone, in particular its bimodal distribution, provides an unambiguous signal for the Bose condensation. We confirm this point with detailed calculation of the change in the atomic momentum distribution across the condensation phase transition, taking into account both the global trapping potential and the atomic interaction effects.