Dynamics of pair correlations in the attractive Lieb-Liniger gas

TL;DR

This paper studies the post-quench dynamics of a 1D Bose gas transitioning from a strongly repulsive to an attractive regime, revealing observable oscillations due to two-particle bound states.

Contribution

It provides an analytical and numerical analysis of pair correlations in the attractive Lieb-Liniger gas, highlighting the role of bound states in the dynamics.

Findings

Observation of density-density correlation oscillations at the pair binding energy

Small admixture of two-particle bound states significantly affects local correlations

Bound states with more than two particles are negligible in the dynamics

Abstract

We investigate the dynamics of a 1D Bose gas after a quench from the Tonks-Girardeau regime to the regime of strong attractive interactions applying analytical techniques and exact numerical simulations. After the quench the system is found to be predominantly in an excited gas-like state, the so-called super-Tonks gas, however with a small coherent admixture of two-particle bound states. Despite its small amplitude, the latter component leads to a rather pronounced oscillation of the local density-density correlation with a frequency corresponding to the binding energy of the pair, making two-particle bound states observable in an experiment. Contributions from bound states with larger particle numbers are found to be negligible.