Renormalization Group Approach to Non-equilibrium Green Functions in Correlated Impurity Systems

TL;DR

This paper introduces a renormalization group method for computing non-equilibrium Green functions in correlated impurity systems, enabling analysis of their dynamics after sudden disturbances.

Contribution

It develops a novel RG-based technique for non-equilibrium Green functions in impurity models, inspired by x-ray response calculations.

Findings

Successfully applied to the ohmic two-state problem.

Provides a framework for initial and final state analysis.

Enhances understanding of non-equilibrium dynamics in impurity systems.

Abstract

We present a technique for calculating non-equilibrium Green functions for impurity systems with local interactions. We use an analogy to the calculation of response functions in the x-ray problem.The initial state and the final state problems, which correspond to the situations before and after the disturbance (an electric or magnetic field, for example) is suddenly switched on, are solved with the aid of Wilson's momentum shell renormalization group. The method is illustrated by calculating the non-equilibrium dynamics of the ohmic two-state problem.