Flow-based sampling in the lattice Schwinger model at criticality

Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany Recent results suggest that flow-based algorithms may provide efficient sampling of field distributions for lattice field theory applications, such as studies of quantum chromodynamics and the Schwinger model. In this work, we provide a numerical demonstration of robust flow-based sampling in the Schwinger model at the critical value of the fermion mass. In contrast, at the same parameters, conventional methods fail to sample all parts of configuration space, leading to severely underestimated uncertainties. Many important physical systems across particle and condensed matter physics can be described in the language of quantum field theory (QFT). Autocorrelations may become especially severe if MCMC updates are configurations, which generates samples by continuously unlikely to generate transitions between modes that are evolving the fields through configuration space via Hamiltonian separated in configuration space.