Maxwell's Refrigerator: An Exactly Solvable Model

TL;DR

This paper presents an exactly solvable model of a Maxwell's refrigerator that transfers heat from cold to hot by utilizing information processing, illustrating the interplay between thermodynamics and information theory.

Contribution

It introduces a simple, solvable model demonstrating how information processing enables heat transfer against a thermal gradient, expanding understanding of thermodynamics and information.

Findings

Model can transfer heat from cold to hot by rectifying thermal fluctuations

Device's operation involves a memory register storing information

The model can also function as an information eraser

Abstract

We describe a simple and solvable model of a device that -- like the "neat-fingered being" in Maxwell's famous thought experiment -- transfers energy from a cold system to a hot system by rectifying thermal fluctuations. In order to accomplish this task, our device requires a memory register to which it can write information: the increase in the Shannon entropy of the memory compensates the decrease in the thermodynamic entropy arising from the flow of heat against a thermal gradient. We construct the nonequilibrium phase diagram for this device, and find that it can alternatively act as an eraser of information. We discuss our model in the context of the second law of thermodynamics.