Modeling Maxwell's demon with a microcanonical Szilard engine

TL;DR

This paper models a classical Hamiltonian system inspired by Maxwell's demon and Szilard engine concepts, demonstrating how energy can be extracted from a heat bath through a cyclic process that involves measurement, linking work and information.

Contribution

It introduces a new Hamiltonian system that mimics Maxwell's demon, explicitly relating work extraction to information gained during measurement.

Findings

Energy is reduced during adiabatic cycling of the system.

Work extracted from the heat bath is quantitatively linked to measurement information.

The apparent violation of the second law is resolved through this relationship.

Abstract

Following recent work by Marathe and Parrondo [PRL, 104, 245704 (2010)], we construct a classical Hamiltonian system whose energy is reduced during the adiabatic cycling of external parameters, when initial conditions are sampled microcanonically. Combining our system with a device that measures its energy, we propose a cyclic procedure during which energy is extracted from a heat bath and converted to work, in apparent violation of the second law of thermodynamics. This paradox is resolved by deriving an explicit relationship between the average work delivered during one cycle of operation, and the average information gained when measuring the system's energy.