title: Absence of single-particle Bose-Einstein condensation at low densities for bosons with correlated hopping.
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.
authors.affiliation: Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne, CH 1015 Lausanne, Switzerland.
authors.forename: Rachel
authors.initials: R
authors.lastname: Bendjama
authors.forename: Brijesh
authors.initials: B
authors.lastname: Kumar
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mila