Band Gap Closing in a Synthetic Hall Tube of Neutral Fermions

TL;DR

This paper reports the experimental creation of a synthetic three-leg Hall tube with ultracold fermions, demonstrating a band gap closing indicative of a topological phase transition through quench dynamics analysis.

Contribution

It introduces a novel experimental realization of a synthetic Hall tube with ultracold atoms and observes topological phase transition signatures.

Findings

Observation of band gap closing at a critical inter-leg coupling.

Detection of topological phase transition via quench dynamics.

Implementation of cyclic inter-leg links using Raman transitions.

Abstract

We report the experimental realization of a synthetic three-leg Hall tube with ultracold fermionic atoms in a one-dimensional optical lattice. The legs of the synthetic tube are composed of three hyperfine spin states of the atoms, and the cyclic inter-leg links are generated by two-photon Raman transitions between the spin states, resulting in a uniform gauge flux $\phi$ penetrating each side plaquette of the tube. Using quench dynamics, we investigate the band structure of the Hall tube system for a commensurate flux $\phi=2\pi/3$. Momentum-resolved analysis of the quench dynamics reveals that a critical point of band gap closing as one of the inter-leg coupling strengths is varied, which is consistent with a topological phase transition predicted for the Hall tube system.