Strongly interacting bosons in a 1D optical lattice at incommensurate densities

TL;DR

This paper explores quantum phase transitions in strongly interacting 1D ultracold bosons, revealing a rich phase diagram including superfluid, supersolid, and solid phases, even with only short-range interactions.

Contribution

It demonstrates that supersolid phases can emerge in short-range interaction models when quantum fluctuations are properly considered, challenging previous assumptions.

Findings

Identification of superfluid, supersolid, and solid phases at incommensurate densities

Supersolids can arise without long-range interactions due to quantum fluctuations

Rich phase diagram with multiple quantum phase transitions

Abstract

We investigate quantum phase transitions occurring in a system of strongly interacting ultracold bosons in a 1D optical lattice. After discussing the commensurate-incommensurate transition, we focus on the phases appearing at incommensurate filling. We find a rich phase diagram, with superfluid, supersolid and solid (kink-lattice) phases. Supersolids generally appear in theoretical studies of systems with long-range interactions; our results break this paradigm and show that they may also emerge in models including only short-range (contact) interactions, provided that quantum fluctuations are properly taken into account.