Kinetic Schemes in Open Interacting Systems

TL;DR

This paper examines the use of kinetic schemes to describe vibrational energy relaxation in open systems, highlighting limitations of standard approaches and connecting them with nonequilibrium Green's function analysis.

Contribution

It introduces a framework for understanding kinetic schemes beyond the standard timescale separation assumption, linking them with NEGF methods in molecular junctions.

Findings

Standard kinetic equations may fail when bath dynamics are not fast

Ignoring timescale breakdown leads to incorrect predictions

Connection established between kinetic schemes and NEGF analysis

Abstract

We discuss utilization of kinetic schemes for description of open interacting systems, focusing on vibrational energy relaxation for an oscillator coupled to a nonequilibirum electronic bath. Standard kinetic equations with constant rate coefficients are obtained under the assumption of timescale separation between system and bath, with the bath dynamics much faster than that of the system of interest. This assumption may break down in certain limits and we show that ignoring this may lead to qualitatively wrong predictions. Connection with more general, nonequilibrium Green's function (NEGF) analysis, is demonstrated. Our considerations are illustrated within generic molecular junction models with electron-vibration coupling.