Semi-synthetic zigzag optical lattice for ultracold bosons

TL;DR

This paper explores a semi-synthetic zigzag optical lattice with tunable magnetic flux affecting ultracold bosons, revealing a novel gapped phase at fractional filling due to the interplay of frustration and interactions.

Contribution

It introduces a semi-synthetic zigzag lattice with nonlocal interactions and analyzes its ground states, uncovering an exotic gapped phase at fractional filling.

Findings

Discovery of a gapped phase at fractional filling factors.

Identification of the role of magnetic flux in inducing frustration.

Observation of nonlocal interactions affecting ground-state properties.

Abstract

We consider a one-dimensional "zigzag" lattice, pictured as a two-site wide single strip taken from a triangular lattice, affected by a tunable homogeneous magnetic flux piercing its triangular plaquettes. We focus on a semi-synthetic lattice produced by combining a one-dimensional spin-dependent lattice in the long direction with laser-induced transitions between atomic internal states that define the short synthetic dimension. In contrast to previous studies on semi-synthetic lattices, the atom-atom interactions are nonlocal in both lattice directions. We investigate the ground-state properties of the system for the case of strongly interacting bosons, and find that the interplay between the frustration induced by the magnetic field and the interactions gives rise to an exotic gapped phase at fractional filling factors corresponding to one particle per magnetic unit cell.