Theoretical constraints on reciprocal and non-reciprocal many-body radiative heat transfer

TL;DR

This paper explores the fundamental physical constraints on many-body radiative heat transfer, considering both reciprocal and non-reciprocal systems, using symmetry principles and thermodynamics to identify conditions for persistent heat currents.

Contribution

It introduces a systematic approach to analyze symmetry constraints and thermodynamic laws on many-body heat transfer, including the existence of persistent heat currents.

Findings

Symmetry of systems forms a magnetic group affecting heat transfer constraints.

Second law imposes a nodal conservation law at equilibrium.

Method to determine persistent heat currents in arbitrary systems.

Abstract

We study the constraints on reciprocal and non-reciprocal many-body radiative heat transfer imposed by symmetry and the second law of thermodynamics. We show that the symmetry of such a many-body system in general forms a magnetic group, and the constraints of the magnetic group on the heat transfer can be derived using a generalized reciprocity theorem. We also show that the second law of thermodynamics provides additional constraints in the form of a nodal conservation law of heat flow at equilibrium. As an application, we provide a systematic approach to determine the existence of persistent heat current in arbitrary many-body systems.