The Broken Engine of Szilard

Abstract

A crucial step in the operation of the Szilard engine is the isothermal expansion of a single particle system. This expansion, seemingly a natural consequence, is unable to proceed when the piston is considered appropriately to be a thermal system subject to fluctuations in energy at a constant temperature. The Szilard engine is thus unable to complete its cycle and the effort to locate the mysterious missing entropy of turns out to be superfluous.