A heat pump at a molecular scale controlled by a mechanical force

TL;DR

This paper demonstrates that a mesoscopic system like Feynman's ratchet can operate as a heat pump at molecular scales, driven by mechanical force, with underlying physical principles clarified through Onsager relations.

Contribution

It introduces a molecular-scale heat pump mechanism using a particle in an asymmetric structure, elucidating the physical basis and Onsager reciprocity in such systems.

Findings

System can transfer heat between baths when dragged

Reciprocity coefficient relates heat transfer and diffusion

Effective heat pumping at molecular energy scales

Abstract

We show that a mesoscopic system such as Feynman's ratchet may operate as a heat pump, and clarify a underlying physical picture. We consider a system of a particle moving along an asymmetric periodic structure . When put into a contact with two distinct heat baths of equal temperature, the system transfers heat between two baths as the particle is dragged. We examine Onsager relation for the heat flow and the particle flow, and show that the reciprocity coefficient is a product of the characteristic heat and the diffusion constant of the particle. The characteristic heat is the heat transfer between the baths associated with a barrier-overcoming process. Because of the correlation between the heat flow and the particle flow, the system can work as a heat pump when the particle is dragged. This pump is particularly effective at molecular scales where the energy barrier is of the order of the thermal energy.