Quasi-one-dimensional Bose gases with large scattering length

TL;DR

This paper explores the behavior of highly elongated Bose gases with large scattering lengths, revealing a unitary regime where properties become independent of the 3d scattering length, and demonstrating the effectiveness of a 1d contact interaction model.

Contribution

It introduces the existence of a unitary regime in quasi-1d Bose gases and validates a 1d contact interaction model for describing their properties across various interaction strengths.

Findings

Properties are well reproduced by a 1d contact interaction model.

Existence of a unitary regime where properties are independent of the 3d scattering length.

Energy in the unitary regime is described by a hard rod equation of state.

Abstract

Bose gases confined in highly-elongated harmonic traps are investigated over a wide range of interaction strengths using quantum Monte Carlo techniques. We find that the properties of a Bose gas under tight transverse confinement are well reproduced by a 1d model Hamiltonian with contact interactions. We point out the existence of a unitary regime, where the properties of the quasi-1d Bose gas become independent of the actual value of the 3d scattering length. In this unitary regime, the energy of the system is well described by a hard rod equation of state. We investigate the stability of quasi-1d Bose gases with positive and negative 3d scattering length.