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Non-equilibrium distributions can be a new power source

​​Researchers from Chalmers, Universidad Autónoma de Madrid, Université Grenoble Alpes and CNRS, show that non-equilibrium distributions can be a new power source. "It is very appealing to think that we might be able to take such a distribution as a resource, and recycle it for power production", says Janine Splettstößer, professor in theoretical physics at the Applied Quantum Physics Laboratory (AQP) at the Department of Microtechnology and Nanoscience – MC2.
Non-equilibrium distributions of states are all around us, and are often generated as an unwanted by-product of some physical process. In the article "Nonequilibrium System as a Demon", recently published in the scientific journal Physical Review Letters, the researchers find that such distributions can be a new power source.
"They generate a paradoxical effect similar to a "Maxwell demon", whereby they reduce another system's entropy at no apparent cost, suggesting that perpetual motion is possible", says Janine Splettstößer (to the left).
The researchers call this a "N-demon" (with the "N" for non-equilibrium). 

Maxwell's demon is a thought experiment created by the physicist James Clerk Maxwell in 1867 in which he suggested how the second law of thermodynamics might hypothetically be violated. In 1982, the physicist Charles H Bennett showed that the paradox of the Maxwell demon was resolved by treating information as a thermodynamic resource like heat or work.
"Similarly, we resolve the paradox of the N-demon by treating "non-equilibrium" as a thermodynamic resource, which is used up as it reduces another system's entropy. This forbids the building of a perpetual motion machine, but does allow us to propose devices that use such resources (in particular non-equilibrium distributions of electrons or photons) to generate more power than is conventionally believed possible", explains Janine Splettstößer.

Her co-authors are Rafael Sánchez, Universidad Autónoma de Madrid, Spain, and Robert S Whitney, Université Grenoble Alpes and CNRS in France.

Text and photo: Michael Nystås
Illustration: Janine Splettstößer

Read the article "Nonequilibrium System as a Demon" in Physical Review Letters >>>
Rafael Sánchez, Janine Splettstoesser, Robert S. Whitney: Nonequilibrium System as a Demon​. Phys. Rev. Lett. 123, 216801 (2019)

Published: Mon 13 Jan 2020.