Quench dynamics of a Bose-Einstein condensate under synthetic spin-orbit coupling

TL;DR

This paper explores the non-equilibrium dynamics of a Bose-Einstein condensate with synthetic spin-orbit coupling after a sudden parameter change, revealing steady states characterized by oscillating momentum distributions and generalized Gibbs ensemble descriptions.

Contribution

It introduces a self-consistent Bogoliubov approach to model quench dynamics in spin-orbit coupled Bose-Einstein condensates, analyzing steady states and momentum distributions.

Findings

Steady states exhibit oscillating momentum distributions and stationary condensate fractions.

Long-time momentum averages are described by a generalized Gibbs ensemble with two temperature branches.

Quench parameters significantly influence the condensate fraction and dynamics.

Abstract

We study the quench dynamics of a Bose-Einstein condensate under a Raman-assisted synthetic spin-orbit coupling. To model the dynamical process, we adopt a self-consistent Bogoliubov approach, which is equivalent to applying the time-dependent Bogoliubov-de-Gennes equations. We investigate the dynamics of the condensate fraction as well as the momentum distribution of the Bose gas following a sudden change of system parameters. Typically, the system evolves into a steady state in the long-time limit, which features an oscillating momentum distribution and a stationary condensate fraction which is dependent on the quench parameters. We investigate how different quench parameters such as the inter- and intra-species interactions and the spin-orbit-coupling parameters affect the condensate fraction in the steady state. Furthermore, we find that the time average of the oscillatory momentum distribution in the long-time limit can be described by a generalized Gibbs ensemble with two branches of momentum-dependent Gibbs temperatures. Our study is relevant to the experimental investigation of dynamical processes in a spin-orbit coupled Bose-Einstein condensate.