Sampling Using Su(N) Gauge Equivariant Flows

We develop a flow-based sampling algorithm for SU(N) lattice gauge theories that is gauge invariant by construction. Our key contribution is constructing a class of flows on an SU(N) variable [or on a U(N) variable by a simple alternative] that respects matrix conjugation symmetry. We apply this technique to sample distributions of single SU(N) variables and to construct flow-based samplers for SU(2) and SU(3) lattice gauge theory in two dimensions.