Evidence for the super Tonks-Girardeau gas

TL;DR

This paper provides experimental evidence supporting the existence of a super Tonks-Girardeau gas-like state in attractive quasi-one-dimensional Bose gases, revealing a highly-excited Bethe state with unique properties.

Contribution

It demonstrates the realization of a super Tonks-Girardeau state as a highly-excited Bethe state in an attractive Bose gas, expanding understanding of strongly correlated quantum gases.

Findings

Identification of a super Tonks-Girardeau-like state in attractive regime

Smooth variation of properties from strong repulsion to attraction

Discovery of a stable phase with two-body bound states

Abstract

We provide evidence in support of a recent proposal by Astrakharchik at al. for the existence of a super Tonks-Girardeau gas-like state in the attractive interaction regime of quasi-one-dimensional Bose gases. We show that the super Tonks-Giradeau gas-like state corresponds to a highly-excited Bethe state in the integrable interacting Bose gas for which the bosons acquire hard-core behaviour. The gas-like state properties vary smoothly throughout a wide range from strong repulsion to strong attraction. There is an additional stable gas-like phase in this regime in which the bosons form two-body bound states behaving like hard-core bosons.