Feynman's ratchet and pawl: an exactly solvable model

TL;DR

This paper presents an exactly solvable discrete model of Feynman's ratchet and pawl, analyzing its steady-state motion and heat flows, and demonstrating its dual role as a heat engine and refrigerator.

Contribution

It introduces a simple, exactly solvable model for Feynman's ratchet and pawl, providing analytical solutions for steady-state behavior and confirming linear response predictions.

Findings

Model operates as heat engine and refrigerator

Exact solutions for steady-state motion and heat flows

Behavior near equilibrium matches linear response theory

Abstract

We introduce a simple, discrete model of Feynman's ratchet and pawl, operating between two heat reservoirs. We solve exactly for the steady-state directed motion and heat flows produced, first in the absence and then in the presence of an external load. We show that the model can act both as a heat engine and as a refrigerator. We finally investigate the behavior of the system near equilibrium, and use our model to confirm general predictions based on linear response theory.