Feynman's ratchet and pawl: an exactly solvable model

C. Jarzynski, O. Mazonka

Published 1999-02-03, updated 1999-06-16Version 2

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.