Pairing, off-diagonal long-range order, and quantum phase transition in strongly attracting ultracold Bose gas mixtures in tight waveguides

TL;DR

This paper models a 1D Bose gas mixture with strong interspecies attraction, revealing the absence of individual BEC and AB-pair ODLRO, but the presence of same-species pair ODLRO, and identifies a quantum phase transition driven by interaction tuning.

Contribution

It provides an exact solution for a 1D Bose mixture with strong AB attraction and uncovers a quantum phase transition related to off-diagonal long-range order.

Findings

No BEC or AB-pair ODLRO in the original model.

Existence of AA and BB pair ODLRO.

Quantum phase transition induced by interaction modifications.

Abstract

A model of two 1D ideal Bose gases A and B with strong AB attractions induced by a p-wave AB Feshbach resonance is studied. The model is solved exactly by a Bose-Bose duality mapping, and it is shown that there is no A-component or B-component Bose-Einstein condensation and no AB-pair off-diagonal long-range order (ODLRO), but both AA-pair and BB-pair ODLRO. After generalization by adding even-wave AA and BB repulsion and reducing the strength of the odd-wave AB attraction by Feshbach resonance detuning, a quantum phase transition occurs between a phase with AB contact nodes and one with no such nodes.