Trace of broken integrability in stationary correlation properties

TL;DR

This paper investigates how breaking integrability in a 1D bosonic system affects stationary correlations, revealing more pronounced changes and interference patterns, especially near the Tonks-Girardeau regime.

Contribution

It introduces a variational Jastrow ansatz for non-integrable cases and compares correlation properties with the integrable Lieb-Liniger model, providing explicit analytical expressions.

Findings

Correlations are more stable near the Tonks-Girardeau regime.

Breaking integrability causes significant changes in correlation patterns.

Additional interference peaks appear in non-integrable cases.

Abstract

We show that the breaking of integrability in the fundamental one-dimensional model of bosons with contact interactions has consequences on the stationary correlation properties of the system. We calculate the energies and correlation functions of the integrable Lieb-Liniger case, comparing the exact Bethe-ansatz solution with a corresponding Jastrow ansatz. Then we examine the non-integrable case of different interaction strengths between each pair of atoms by means of a variationally optimized Jastrow ansatz, proposed in analogy to the Laughlin ansatz. We show that properties of the integrable state are more stable close to the Tonks-Girardeau regime than for weak interactions. All energies and correlation functions are given in terms of explicit analytical expressions enabled by the Jastrow ansatz. We finally compare the correlations of the integrable and non-integrable cases and show that apart from symmetry breaking the behavior changes dramatically, with additional and more pronounced maxima and minima interference peaks appearing.