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Physics

Maxwell's demon experiment could be made real without breaking physics

A thought experiment called Maxwell’s demon, long hypothesised to break the laws of physics, could be made using simple electronic devices at macroscopic scales – without upsetting the laws of thermodynamics

By Leah Crane

10 May 2022

Illustration of a computer motherboard with microchips, transistors and semiconductors.

An illustration of a computer motherboard with transistors

EDUARD MUZHEVSKYI / SCIENCE PHOTO LIBRARY

A 155-year-old thought experiment, long thought to break the laws of thermodynamics, could be made real on a large scale.

Maxwell’s demon is a thought experiment first proposed by Scottish mathematician James Clerk Maxwell in 1867. He imagined a tiny demon controlling a door between two gas-filled chambers of a box. By carefully opening and closing the door, the demon allows only fast-moving gas particles into one chamber and slow-moving ones into the other. Because the speed of its particles determines a gas’s temperature,…

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