Absence of single particle Bose-Einstein condensation at low densities for bosons with correlated-hopping

TL;DR

This paper investigates a 2D bosonic model with correlated-hopping, revealing a pairing phase without single particle BEC at low densities and a phase transition to BEC at higher densities, with implications for quantum spin systems.

Contribution

It introduces a mean-field analysis of correlated-hopping bosons, showing a pairing phase without BEC and identifying a quantum phase transition, which advances understanding of bosonic and spin systems.

Findings

Pairing phase exists without single particle BEC at low densities.

A quantum phase transition to BEC occurs at higher densities.

Implications for frustrated quantum magnets and spin systems.

Abstract

Motivated by the physics of mobile triplets in frustrated quantum magnets, the properties of a two dimensional model of bosons with correlated-hopping are investigated. A mean-field analysis reveals the presence of a pairing phase without single particle Bose-Einstein condensation (BEC) at low densities for sufficiently strong correlated-hopping, and of an Ising quantum phase transition towards a BEC phase at larger density. The physical arguments supporting the mean-field results and their implications for bosonic and quantum spin systems are discussed.