Quantum phases of dipolar bosons in multilayer optical lattice

TL;DR

This paper explores the quantum phases of dipolar bosons in multilayer optical lattices, revealing multimer formation, checkerboard ordering, and resonating valence-bond states driven by interactions and hopping.

Contribution

It introduces a variant of the extended Bose-Hubbard model for multilayer dipolar atoms and analyzes the resulting quantum phases using analytical and mean-field methods.

Findings

Multimer formation occurs in weak hopping regimes due to attractive interactions.

Checkerboard multimer phase emerges at half-filling from repulsive intralayer interactions.

Resonating valence-bond states form at higher interlayer hopping.

Abstract

We consider a minimal model to investigate the quantum phases of hardcore, polarized dipolar atoms confined in multilayer optical lattices. The model is a variant of the extended Bose-Hubbard model, which incorporates intralayer repulsion and interlayer attraction between the atoms in nearest-neighbour sites. We study the phases of this model emerging from the competition between the attractive interlayer interaction and the interlayer hopping. Our results from the analytical and cluster-Gutzwiller mean-field theories reveal that multimer formation occurs in the regime of weak intra and interlayer hopping due to the attractive interaction. In addition, intralayer isotropic repulsive interaction results in the checkerboard ordering of the multimers. This leads to an incompressible checkerboard multimer phase at half-filling. At higher interlayer hopping, the multimers are destabilized to form resonating valence-bond like states. Furthermore, we discuss the effects of thermal fluctuations on the quantum phases of the system.