Chiral dynamics of ultracold atoms under a tunable SU(2) synthetic gauge field

Surface currents arise in superconductors under magnetic fields and are a key signature of the Meissner effect. Similarly, chiral dynamics have been observed in quantum simulators under synthetic Abelian gauge fields. These simulators offer flexible control, enabling the engineering of non-Abelian gauge fields, although their influence on chiral dynamics remains unclear. Here, we implement a synthetic SU(2) gauge field in a spinful one-dimensional ladder and investigate the resulting chiral dynamics by developing a Raman momentum-lattice technique. We confirm the non-Abelian nature of the synthetic potential by observing the non-Abelian Aharonov–Bohm effect on a single plaquette. Furthermore, we find that the chiral current along the two legs of the ladder is spin dependent and highly tunable through the gauge potential parameters. We experimentally map out different dynamic regimes of the chiral current, revealing the competition between overlaying flux ladders with different spin compositions. Our experiment demonstrates the impact of non-Abelian gauge fields on chiral dynamics and offers a viable approach to implementing exotic synthetic gauge fields using Raman momentum lattices. The implementation of synthetic Abelian gauge fields in quantum simulators can result in chiral edge currents. The impact of non-Abelian gauge fields on chiral dynamics of ultracold atoms is now explored using a momentum-space lattice technique.