Realization of a Synthetic Hall Torus with a Spinor Bose-Einstein Condensate

TL;DR

This paper reports the first experimental creation of a synthetic Hall torus using a spinor Bose-Einstein condensate in a ring trap, demonstrating control over topological features and density modulations related to quantum Hall physics.

Contribution

The work introduces a novel experimental realization of a synthetic Hall torus with controllable topological properties using a spinor Bose-Einstein condensate.

Findings

Imposed periodic boundary conditions in the synthetic dimension.

Controlled azimuthal density modulations via synthetic magnetic flux.

Transition observed from cylindrical to toroidal topology.

Abstract

We report the first experimental realization of a synthetic Hall torus using a spinor Bose-Einstein condensate confined in a ring-shaped trap with in situ imaging. By cyclically coupling three hyperfine spin states via Raman and microwave fields, we impose a periodic boundary condition in the synthetic dimension, which together with a real-space ring trap, realizes a toroidal geometry with a synthetic magnetic flux. This flux induces azimuthal density modulations in the condensate, whose periodicity is uniquely determined by the quantized toroidal magnetic flux-a hallmark of the Hall torus geometry. By varying the relative phase between the couplings across repeated experimental runs, we control the location of the density extrema, emulating the behavior of Thouless charge pump in a toroidal geometry. We further investigate the onset of these modulations as the system transitions from a cylindrical to a toroidal topology. Our results establish a versatile platform for investigating quantum Hall physics and topological phenomena in synthetic curved spaces.