Phase Coherence and Fragmentation of Two-Component Bose-Einstein Condensates Loaded in State-Dependent Optical Lattices

TL;DR

This study investigates how internal mean-field lattices formed by one component of a two-component Bose-Einstein condensate can induce phase decoherence, revealing limitations compared to external optical lattices.

Contribution

It demonstrates through numerical simulations that internal mean-field lattices can cause phase decoherence, but their effect is limited relative to external optical lattices.

Findings

Internal mean-field lattices can induce phase decoherence.

The effect of internal lattices on coherence is limited.

External optical lattices cause more significant decoherence.

Abstract

A binary mixture of interacting Bose-Einstein condensates (BEC) in the presence of fragmentation-driving external lattice potentials forms two interdependent mean-field lattices made of each component. These effective mean-field lattices, like ordinary optical lattices, can induce additional fragmentation and phase coherence loss of BECs between lattice sites. In this study, we consider the nonequilibrium dynamics of two hyperfine states of one-dimensional Bose-Einstein condensates, subjected to state-dependent optical lattices. Our numerical calculations using the truncated Wigner approximation (TWA) show that phase coherence in a mixture of two-component BECs can be lost not just by optical lattices, but by mean-field lattices gradually formed by other components, and we reveal that such an effect of internal mean-field lattices, however, is limited, contrary to external optical lattices, in regard to phase decoherence.