Cold-atoms on a two-dimensional square optical lattice with an alternating potential

TL;DR

This study investigates a two-dimensional square optical lattice with cold atoms modeled by hard-core bosons, revealing the emergence of a supersolid phase influenced by the strength of an alternating potential.

Contribution

It demonstrates how an alternating potential induces a supersolid phase in a 2D optical lattice, with phase transitions depending on potential strength and boson density.

Findings

Supersolid phase appears across most densities with weak potential.

Strong potential leads to supersolid, Mott insulator, and charge density wave phases.

Supersolid exists except at half-filling where Mott insulator occurs.

Abstract

The cold-atom on a two-dimensional square optical lattice is studied within the hard-core boson Hubbard model with an alternating potential. In terms of the quantum Monte Carlo method, it is shown explicitly that a supersolid phase emerges due to the presence of the alternating potential. For the weak alternating potential, the supersolid state appears for the whole range of hard-core boson densities except the half-filling case, where the system is a Mott insulator. However, for the strong alternating potential, besides the supersolid and Mott insulating states, a charge density wave phase appears.