Ultra-cold bosons in zig-zag optical lattices

TL;DR

This paper explores the complex phases of ultra-cold bosons in zig-zag optical lattices, highlighting how lattice geometry, interactions, and constraints lead to diverse quantum states that can be experimentally realized.

Contribution

It introduces the phase diagram of constrained and unconstrained bosons in zig-zag lattices, revealing novel phases like chiral superfluidity, Haldane-insulator, and pair-superfluidity.

Findings

Unconstrained bosons exhibit chiral superfluidity and Mott-insulator phases at low interactions.

Three-body constraints enable Haldane-insulator and pair-superfluid phases.

Current techniques can create and detect these phases.

Abstract

Ultra-cold bosons in zig-zag optical lattices present a rich physics due to the interplay between frustration, induced by lattice geometry, two-body interaction and three-body constraint. Unconstrained bosons may develop chiral superfluidity and a Mott-insulator even at vanishingly small interactions. Bosons with a three-body constraint allow for a Haldane-insulator phase in non-polar gases, as well as pair-superfluidity and density wave phases for attractive interactions. These phases may be created and detected within the current state of the art techniques.