Real-Time Dynamics in Quantum Impurity Models with Diagrammatic Monte Carlo

TL;DR

This paper introduces an advanced real-time Diagrammatic Monte Carlo method for quantum impurity models, enabling the study of non-equilibrium dynamics from arbitrary initial states, with applications to quantum quenches in the Anderson model.

Contribution

It extends the hybridization expansion Diagrammatic Monte Carlo method to the full Kadanoff-Baym-Keldysh contour, allowing for more general initial conditions in real-time simulations.

Findings

Successfully applied to non-equilibrium dynamics after a quantum quench in the Anderson model.

Enables use as a solver for Non Equilibrium Dynamical Mean Field Theory.

Provides a versatile tool for studying real-time dynamics in correlated impurity systems.

Abstract

We extend the recently developed real-time Diagrammatic Monte Carlo method, in its hybridization expansion formulation, to the full Kadanoff-Baym-Keldysh contour. This allows us to study real-time dynamics in correlated impurity models starting from an arbitrary, even interacting, initial density matrix. As a proof of concept we apply the algorithm to study the non equilibrium dynamics after a local quantum quench in the Anderson Impurity Model. Being a completely general approach to real-time dynamics in quantum impurity models it can be used as a solver for Non Equilibrium Dynamical Mean Field Theory.