Chiral Dynamics of Ultracold Atoms under a Tunable SU(2) Synthetic Gauge Field

TL;DR

This paper demonstrates the implementation of a tunable SU(2) synthetic gauge field in ultracold atoms, revealing spin-dependent chiral currents and non-Abelian effects, advancing understanding of non-Abelian gauge fields in quantum simulators.

Contribution

The study introduces a novel experimental realization of a synthetic SU(2) gauge field in a 1D ladder system, showcasing non-Abelian effects and tunable chiral dynamics.

Findings

Observation of non-Abelian Aharonov-Bohm effect

Detection of spin-dependent, tunable chiral currents

Mapping of different dynamic regimes of chiral current

Abstract

Surface currents emerge in superconductors exposed to magnetic fields, and are a key signature of the Meissner effect. Analogously, chiral dynamics were observed in quantum simulators under synthetic Abelian gauge fields. The flexible control of these simulators also facilitates the engineering of non-Abelian gauge fields, but their impact on the chiral dynamics remains elusive. Here, by employing the cutting-edge momentum-lattice technique, we implement a synthetic SU(2) gauge field in a spinful 1D ladder and study the rich chiral dynamics therein. We confirm the non-Abelian nature of the synthetic potential by observing the non-Abelian Aharonov-Bohm effect on a single plaquette. More importantly, the chiral current along the two legs of the ladder is observed to be spin-dependent and highly tunable through the parameters of the gauge potential. We experimentally map out different dynamic regimes of the chiral current, and reveal the underlying competition between overlaying flux ladders with distinct spin compositions. Our experiment demonstrates the dramatic impact of non-Abelian gauge fields on the system dynamics, paving the way for future studies of exotic synthetic gauge fields on the versatile platform of momentum lattices.