Non-Abelian dynamical gauge field and topological superfluids in optical Raman lattice

Abstract We propose a novel scheme to realize non-Abelian dynamical gauge field for ultracold fermions, and uncover a new pairing mechanism for topological superfluidity. The dynamical gauge fields arise from a nontrivial compensation effect between the large Zeeman detuning and strong Hubbard interaction in a two-dimensional (2D) optical Raman lattice. The spin-flip transitions are forbidden by the large Zeeman detuning, but restored when the Zeeman splitting is compensated by Hubbard interaction, generating a dynamical non-Abelian gauge field that leads to a correlated 2D spin-orbit interaction depending on local state configurations. The topological superfluid from a novel pairing driven by 2D dynamical gauge fields is reached with high feasibility, showing a broad phase region without competing orders at relevant fillings, and can be easily prepared in experiment. Our work can open up an avenue to emulate non-Abelian dynamical gauge fields and exotic correlated topological phases with feasibility and particularly, paves the way for realizing the non-Abelian topological superfluids.