Real-time Kadanoff-Baym approach to plasma oscillations in a correlated electron gas

TL;DR

This paper introduces a real-time nonequilibrium Green's functions method based on Kadanoff-Baym equations to analyze plasma oscillations in correlated electron gases, capturing collision effects efficiently.

Contribution

It presents a novel real-time approach using Kadanoff-Baym equations for plasma oscillations, offering a simpler and consistent alternative to traditional equilibrium methods.

Findings

Accurately computes plasmon spectra with collision effects.

Preserves sum rules automatically.

Simpler numerical implementation than Bethe-Salpeter based methods.

Abstract

A nonequilibrium Green's functions approach to the collective response of correlated Coulomb systems at finite temperature is presented. It is shown that solving Kadanoff-Baym type equations of motion for the two-time correlation functions with the external perturbing field included allows to compute the plasmon spectrum with collision effects in a systematic and consistent way. The scheme has ``built-in'' sum rule preservation and is simpler to implement numerically than the equivalent equilibrium approach based on the Bethe-Salpeter equation.