Generalized projected dynamics for non-system observables of non-equilibrium quantum impurity models

TL;DR

This paper extends the reduced dynamics formalism to include non-system observables like current in non-equilibrium quantum impurity models, enabling more comprehensive analysis of these systems.

Contribution

The authors generalize the reduced dynamics formalism to incorporate non-system observables, such as current, providing a more complete description of non-equilibrium quantum impurity models.

Findings

Formalism successfully applied to a resonant level model

Equation of motion for observables can be closed with the density matrix

Enhanced capability to study non-equilibrium transport phenomena

Abstract

The reduced dynamics formalism has recently emerged as a powerful tool to study the dynamics of non-equilibrium quantum impurity models in strongly correlated regimes. Examples include the non-equilibrium Anderson impurity model near the Kondo crossover temperature and the non-equilibrium Holstein model, for which the formalism provides an accurate description of the reduced density matrix of the system for a wide range of timescales. In this work, we generalize the formalism to allow for non-system observables such as the current between the impurity and leads. We show that the equation of motion for the reduced observable of interest can be closed with the equation of motion for the reduced density matrix and demonstrate the new formalism for a generic resonant level model.