Steady state formulation of Inchworm Monte Carlo

We present an Inchworm method directly formulated in the steady state. Until now, numerically exact real time Monte Carlo methods have simulated steady state dynamics by propagating from a tractable initial condition to long times. The computational cost for accessing nonequilibrium steady states in these methods was often prohibitive. We demonstrate the performance of our steady state method by comparison with analytical results and other numerically exact techniques and showcase its usage within dynamical mean field simulations. The steady state formulation of the Inchworm method closes the gap between short-time dynamics and the long time behavior and extends the applicability of non-equilibrium Monte Carlo methods as impurity solvers within quantum embedding schemes.