Gauge-equivariant flow models for sampling in lattice field theories with pseudofermions
Authors
Abbott, Ryan; Albergo, Michael S; Boyda, Denis; Cranmer, Kyle; Hackett, Daniel C; Kanwar, Gurtej; Racaniere, Sebastien; Rezende, Danilo J; Romero-Lopez, Fernando; Shanahan, Phiala E ; Tian, Betsy; Urban, Julian M
Abstract
This work presents gauge-equivariant architectures for flow-based sampling in fermionic lattice field theories using pseudofermions as stochastic estimators for the fermionic determinant. This is the default approach in state-of-the-art lattice field theory calculations, making this development critical to the practical application of flow models to theories such as QCD. Methods by which flow-based sampling approaches can be improved via standard techniques such as even/odd preconditioning and the Hasenbusch factorization are also outlined. Numerical demonstrations in two-dimensional U(1) and SU(3) gauge theories with Nf 1/4 2 flavors of fermions are provided.