ACFlow 2.0 : An open source toolkit for analytic continuation of quantum Monte Carlo data

Analytic continuation is an essential step in quantum Monte Carlo calculations. We present version 2.0 of the ACFlow package, a full-fledged open source toolkit for analytic continuation of quantum Monte Carlo simulation data. The new version adds support for three recently developed analytic continuation methods, namely the barycentric rational function approximation method, the stochastic pole expansion method, and the Nevanlinna analytical continuation method. The well-established maximum entropy method is also enhanced with the Bayesian reconstruction entropy algorithm. Furthermore, a web-based graphical user interface and a testing toolkit for analytic continuation methods are introduced. In this paper, we at first summarize the basic principles of the newly implemented analytic continuation solvers, and the most important improvements of ACFlow 2.0. Then a representative example is provided to demonstrate the new usages and features.