Comparative study of theoretical methods for non-equilibrium quantum transport

Abstract

We present a detailed comparison of three different methods designed to\ntackle nonequilibrium quantum transport, namely the functional renormalization\ngroup (fRG), the time-dependent density matrix renormalization group (tDMRG),\nand the iterative summation of real-time path integrals (ISPI). For the\nnonequilibrium single-impurity Anderson model (including a Zeeman term at the\nimpurity site), we demonstrate that the three methods are in quantitative\nagreement over a wide range of parameters at the particle-hole symmetric point\nas well as in the mixed-valence regime. We further compare these techniques\nwith two quantum Monte Carlo approaches and the time-dependent numerical\nrenormalization group method.\n