Maxwell through the Looking Glass: From Szilard to Landauer and Back Again

Abstract

The Szilard Engine has been used to suggest that the impossibility of an effective Maxwellian Demon is guaranteed by Landauer's Principle in the thermodynamics of computation. Critics suggest that the argument is circular, as Landauer's Principle itself rests upon the assumption that the Second Law is inviolate, and so the impossibility of a Maxwellian Demon remains suspect. We suggest that the correct understanding is that both the failure of the Szilard Engine and the basis of Landauer's Principle are direct, and equivalent, consequences of Hamiltonian dynamics and the normal statistical mechanical assumptions regarding microscopic correlations.