On persistent energy currents at equilibrium in non-reciprocal systems

Fuente: arXiv
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Hauptverfasser: Biehs, Svend-Age, Latella, Ivan
Format: Preprint
Veröffentlicht: 2025
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author Biehs, Svend-Age
Latella, Ivan
author_facet Biehs, Svend-Age
Latella, Ivan
contents We investigate the properties of the mean Poynting vector in global thermal equilibrium, which can be non-zero in non-reciprocal electromagnetic systems. Using dyadic Green's functions and the fluctuation-dissipation theorem, we provide a general proof that the mean Poynting vector is divergence-free under equilibrium conditions. Relying on this proof, we explicitly demonstrate that for systems where a normal mode expansion of the Green's function is applicable, the divergence of the equilibrium mean Poynting vector vanishes. As concrete examples, we also examine the equilibrium mean Poynting vector near a planar non-reciprocal substrate and in configurations involving an arbitrary number of dipolar non-reciprocal objects in free space. Finally, we argue that the so-called persistent heat current, while present in equilibrium, cannot be detected through out-of-equilibrium heat transfer measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2504_21556
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On persistent energy currents at equilibrium in non-reciprocal systems
Biehs, Svend-Age
Latella, Ivan
Mesoscale and Nanoscale Physics
We investigate the properties of the mean Poynting vector in global thermal equilibrium, which can be non-zero in non-reciprocal electromagnetic systems. Using dyadic Green's functions and the fluctuation-dissipation theorem, we provide a general proof that the mean Poynting vector is divergence-free under equilibrium conditions. Relying on this proof, we explicitly demonstrate that for systems where a normal mode expansion of the Green's function is applicable, the divergence of the equilibrium mean Poynting vector vanishes. As concrete examples, we also examine the equilibrium mean Poynting vector near a planar non-reciprocal substrate and in configurations involving an arbitrary number of dipolar non-reciprocal objects in free space. Finally, we argue that the so-called persistent heat current, while present in equilibrium, cannot be detected through out-of-equilibrium heat transfer measurements.
title On persistent energy currents at equilibrium in non-reciprocal systems
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2504.21556