Quantum thermal transport through anharmonic systems: A self-consistent approach

TL;DR

This paper introduces a self-consistent method to analyze quantum thermal transport in anharmonic systems by approximating them with an effective harmonic Hamiltonian, enabling efficient calculations and insights into thermal rectification.

Contribution

It presents a novel self-consistent approach combining phonon theory and Green's functions to study anharmonic quantum thermal transport.

Findings

Effective harmonic Hamiltonian accurately models anharmonic systems.

Method successfully predicts thermal rectification effects.

Approach validated against quantum master equation results.

Abstract

We propose a feasible and effective approach to study quantum thermal transport through anharmonic systems. The main idea is to obtain an {\it effective} harmonic Hamiltonian for the anharmonic system by applying the self-consistent phonon theory. Using the effective harmonic Hamiltonian we study thermal transport within the framework of nonequilibrium Green's function method using the celebrated Caroli formula. We corroborate our quantum self-consistent approach using the quantum master equation that can deal with anharmonicity exactly, but is limited to the weak system-bath coupling regime. Finally, in order demonstrate its strength we apply the quantum self-consistent approach to study thermal rectification in a weakly coupled two segment anharmonic system.