Quench dynamics of a strongly interacting resonant Bose gas

TL;DR

This paper investigates the nonequilibrium dynamics of a strongly interacting Bose gas after a quench near a Feshbach resonance, revealing steady states, deviations from equilibrium, and a possible phase transition to a depleted state.

Contribution

It provides a self-consistent Bogoliubov analysis of quench dynamics near resonance, highlighting nonequilibrium steady states and phase transition phenomena.

Findings

Observation of nonequilibrium steady states with altered momentum distributions

Deviations of depletion, condensate density, and contact from equilibrium values

Prediction of a phase transition to a fully depleted state near resonance

Abstract

We explore the dynamics of a Bose gas following its quench to a strongly interacting regime near a Feshbach resonance. Within a self-consistent Bogoliubov analysis we find that after the initial condensate-quasiparticle Rabi oscillations, at long time scales the gas is characterized by a nonequilibrium steady-state momentum distribution function, with depletion, condensate density and contact that deviate strongly from their corresponding equilibrium values. These are in a qualitative agreement with recent experiments on Rb85 by Makotyn, et al. Our analysis also suggests that for sufficiently deep quenches close to the resonance the nonequilibrium state undergoes a phase transition to a fully depleted state, characterized by a vanishing condensate density.