Probing Maxwell's Demon with a Nanoscale Thermometer

TL;DR

This paper introduces a quantum electron thermometer model and demonstrates how atomic-scale temperature measurements reveal quantum oscillations linked to Maxwell's demon, illustrating the emergence of Fourier's law at larger scales.

Contribution

It develops a realistic model of a nanoscale thermal microscope and connects quantum temperature oscillations to Maxwell's demon at the molecular level.

Findings

Quantum oscillations in atomic orbital temperatures due to Maxwell's demon.

Resolution limits affect the observation of quantum effects.

Fourier's law emerges from coarse-grained temperature measurements.

Abstract

A precise definition for a quantum electron thermometer is given, as an electron reservoir coupled locally (e.g., by tunneling) to a sample, and brought into electrical and thermal equilibrium with it. A realistic model of a scanning thermal microscope with atomic resolution is then developed, where the resolution is limited in ultrahigh vacuum by thermal coupling to the electromagnetic environment. We show that the temperatures of individual atomic orbitals or bonds in a conjugated molecule with a temperature gradient across it exhibit quantum oscillations, whose origin can be traced to a realization of Maxwell's demon at the single-molecule level. These oscillations may be understood in terms of the rules of covalence describing bonding in \pi-electron systems. Fourier's law of heat conduction is recovered as the resolution of the temperature probe is reduced, indicating that the macroscopic law emerges as a consequence of coarse graining.