FisMat2017 - Submission - View

Abstract's title: Phase diagram of a boson synthetic ladder
Submitting author: Roberta Citro
Affiliation: Department of Physics "E.R. Caianiello", University of Salerno
Affiliation Address: Via Giovanni Paolo II, 132 84084 Fisciano (Sa)
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: E. Orignac, Univ. Lyon, Ens de Lyon, Univ. Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon (Fr) S. De Palo, CNR-IOM-Democritos National Simulation Centre, UDS Via Bonomea 265, I-34136, Trieste and Dipartimento di Fisica Teorica, Universita` Trieste, Trieste, Italy M. Di Dio, CNR-IOM-Democritos National Simulation Centre, UDS Via Bonomea 265, I-34136, Trieste and Dipartimento di Fisica Teorica, Universita` Trieste, Trieste, Italy
Abstract

We consider a two-leg boson ladder in an artificial U(1) gauge field and study its phase diagram. In absence of interchain interaction we find a transition from commensurate Meissner to incommensurate Vortex state at increasing interchain hopping till a critical value above which the Meissner state is stable at any flux[1,2]. For flux close to π, and below the critical hopping, we observe the formation of a second incommensuration in the Mott Vortex state[1,2] that could be detectable in current experiments. We then show that, in the presence of interleg attractive interaction, the flux induced Vortex state can be melted by dislocations. For increasing flux, instead of the Meissner to Vortex transition in the commensurate-incommensurate universality class, first an Ising transition from the Meissner state to a charge density wave takes place, then, at higher flux, the melted Vortex phase is established via a disorder point where incommensuration develops in the rung current correlation function and in momentum distribution[3]. Finally, the quasi-long range ordered Vortex phase is recovered for sufficiently small interaction. Our predictions for the observables, such as the spin current and the static structure factor, could be tested in current experiments with cold atoms in bosonic ladders.

[1] M. Di Dio, S. De Palo, E. Orignac, R. Citro, and M.-L. Chiofalo, Phys. Rev. B 92, 060506 (2015)

[2] E. Orignac, R. Citro, M. Di Dio, S. De Palo, and M. L. Chiofalo, New J. Phys. 18, 055017 (2016)

[3] E. Orignac, R. Citro, M. Di Dio and S. De Palo, arxiv 1703.07742 (2017)