Correlation Effects in the Quench-Induced Phase Separation Dynamics of a Two-Species Ultracold Quantum Gas

TL;DR

This paper investigates the complex dynamics of a two-species ultracold quantum gas during phase transitions, revealing filamentation, correlated structures, and entanglement effects beyond mean-field models.

Contribution

It provides a detailed many-body analysis of quench-induced phase separation, highlighting correlation effects and experimental signatures in binary Bose-Einstein condensates.

Findings

Filamentation involves shorter wavenumbers and longer spatial scales in many-body models.

Multiple dark-antidark solitary waves are generated during reverse quenches and decay over time.

Variance growth rate of single-shot images indicates the system's entanglement level.

Abstract

We explore the quench dynamics of a binary Bose-Einstein condensate crossing the miscibility-immiscibility threshold and vice versa, both within and in particular beyond the mean-field approximation. Increasing the interspecies repulsion leads to the filamentation of the density of each species, involving shorter wavenumbers and longer spatial scales in the many-body approach. These filaments appear to be strongly correlated and exhibit domain-wall structures. Following the reverse quench process multiple dark-antidark solitary waves are spontaneously generated and subsequently found to decay in the many-body scenario. We simulate single-shot images to connect our findings to possible experimental realizations. Finally, the growth rate of the variance of a sample of single-shots probes the degree of entanglement inherent in the system.