Commensurate supersolids and re-entrant transitions in an extended Bose-Hubbard ladder

TL;DR

This paper explores novel phases in an extended Bose-Hubbard ladder, revealing the emergence of commensurate supersolids, reentrant transitions, and the effects of inter-chain hopping, with proposals for experimental observation.

Contribution

It demonstrates the existence of a commensurate supersolid in a ladder geometry and classifies phases using the Luttinger parameter, highlighting reentrant behaviors and the impact of inter-chain hopping.

Findings

A commensurate supersolid phase emerges in the ladder.

Reentrant gapless behavior occurs with increasing onsite interaction.

String order vanishes with finite inter-chain hopping.

Abstract

We investigate the ground state phases of an extended Bose-Hubbard ladder of unit filling via the density-matrix-renormalization-group method and, in particular, the effect of rung-hoppings. In contrast to a single-chain, a commensurate supersolid emerges, and based on the Luttinger parameter, we classify them into two types. The latter leads to a reentrant gapless behavior as the onsite interaction is increased while keeping all other parameters intact. A reentrant gapped transition is also found as a function of nearest-neighbor interactions. Further, we show that the string order characterizing the Haldane phase vanishes for a finite inter-chain hopping amplitude, however small it is. Finally, we propose two experimental platforms to observe our findings, using either dipolar atoms or polar molecules and Rydberg admixed atoms.