Quantum phase transitions of a two-leg bosonic ladder in an artificial gauge field

Roberta Citro (1) , S. de Palo (2, 3) , M. Di Dio (3) , E. Orignac (4)

1 Dipartamento di Fisica "E. R. Caianiello"
2 Dipartimento di Fisica Teorica
3 CNR-IOM-Democritos
4 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

We consider a two leg bosonic ladder in a U(1) gauge field with both interleg hopping and interleg repulsion. As a function of the flux, the interleg interaction converts the commensurate-incommensurate transition from the Meissner to a Vortex phase, into an Ising-type of transition towards a density wave phase. A disorder point is also found after which the correlation functions develop a damped sinusoid behavior signaling a melting of the vortex phase. We discuss the differences on the phase diagram for attractive and repulsive interleg interaction. In particular, we show how repulsion favors the Meissner phase at low flux and a phase with a second incommensuration in the correlation functions for intermediate flux, leading to a richer phase diagram than in the case of interleg attraction. The effect of the temperature on the chiral current is also discussed.

Mots clés: Commensurate incommensurate transition; Disorder point; Ising transition; Ultracold Bosons; Artificial gauge fields

Domaines: Gaz Quantiques [cond-mat.quant-gas]; Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Roberta Citro, S. de Palo, M. Di Dio, E. Orignac. Quantum phase transitions of a two-leg bosonic ladder in an artificial gauge field. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2018, 97 (17), pp.174523. ⟨10.1103/PhysRevB.97.174523⟩. ⟨ensl-01813546⟩