Mott-insulator phases of non-locally coupled 1D dipolar Bose gases

TL;DR

This paper investigates how non-local dipole-dipole interactions in 1D bosonic gases lead to a novel Mott-insulator to pair-superfluid transition, altering phase boundaries and resulting in re-entrant behavior, with implications for experimental observations.

Contribution

It introduces the impact of non-local dipolar interactions on Mott-insulator phases, revealing a transition to pair-superfluidity and re-entrant phase behavior not seen in short-range systems.

Findings

Non-local dipole interactions induce a Mott-insulator to pair-superfluid transition.

Re-entrant phase behavior occurs with increasing hopping rate.

Mott-insulator plateaux can widen with increased hopping in certain conditions.

Abstract

We analyze the Mott-insulator phases of dipolar bosonic gases placed in neighboring but unconnected 1D traps. Whereas for short-range interactions the 1D systems are independent, the non-local dipole-dipole interaction induces a direct Mott-insulator to pair-superfluid transition which significantly modifies the boundaries of the lowest Mott-insulator phases. The lowest boundary of the lowest Mott regions becomes progressively constant as a function of the hopping rate, eventually inverting its slope, leading to a re-entrant configuration which is retained in 2D. We discuss the consequences of this effect on the spatial Mott-insulator plateaux in experiments with additional harmonic confinement, showing that anti-intuitively the plateaux may become wider for increasing hopping. Our results are also applicable to non-dipolar boson-boson mixtures.