Speaker
Description
Accurate diagrammatic simulations of nonequilibrium quantum many-body systems are often limited by the evaluation of multidimensional integrals involving high-order correlation functions. In this work, I present a tensor-network acceleration scheme for diagrammatic calculations based on tensor cross interpolation (TCI). The method is applied to the strong-coupling expansion for quantum impurity problems within dynamical mean-field theory (DMFT) and extended DMFT (EDMFT), enabling nonperturbative simulations of nonequilibrium steady states in both the Hubbard and extended Hubbard models. The central idea is to decompose multidimensional diagrammatic kernels on the fly into compact tensor-network representations, thereby substantially reducing the computational cost of evaluating contour-ordered correlators. Beyond impurity solvers, the same framework can be extended to higher-order spectroscopies such as time-resolved resonant inelastic X-ray scattering (tr-RIXS), which require the evaluation of four-point correlation functions.