Auxiliary Master Equation for Nonequilibrium Dual-Fermion Approach

Phys Rev Lett. 2019 May 10;122(18):186803. doi: 10.1103/PhysRevLett.122.186803.


We introduce an auxiliary quantum master equation dual fermion method and argue that it presents a convenient way to describe steady states of correlated impurity models. The scheme yields an expansion around a reference that is much closer to the true nonequilibrium state than that in the original dual fermion formulation. In steady-state situations, the scheme is numerically inexpensive and avoids time propagation. The Anderson impurity model is used to test the approach against numerically exact benchmarks.