scholarly journals Hidden Dissipation and Irreversibility in Maxwell’s Demon

Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 93
Author(s):  
Paul W. Fontana

Maxwell’s demon is an entity in a 150-year-old thought experiment that paradoxically appears to violate the second law of thermodynamics by reducing entropy without doing work. It has increasingly practical implications as advances in nanomachinery produce devices that push the thermodynamic limits imposed by the second law. A well-known explanation claiming that information erasure restores second law compliance fails to resolve the paradox because it assumes the second law a priori, and does not predict irreversibility. Instead, a purely mechanical resolution that does not require information theory is presented. The transport fluxes of mass, momentum, and energy involved in the demon’s operation are analyzed and show that they imply “hidden” external work and dissipation. Computing the dissipation leads to a new lower bound on entropy production by the demon. It is strictly positive in all nontrivial cases, providing a more stringent limit than the second law and implying intrinsic thermodynamic irreversibility. The thermodynamic irreversibility is linked with mechanical irreversibility resulting from the spatial asymmetry of the demon’s speed selection criteria, indicating one mechanism by which macroscopic irreversibility may emerge from microscopic dynamics.

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 269
Author(s):  
Orly Shenker ◽  
Meir Hemmo

Maxwell’s Demon is a thought experiment devised by J. C. Maxwell in 1867 in order to show that the Second Law of thermodynamics is not universal, since it has a counter-example. Since the Second Law is taken by many to provide an arrow of time, the threat to its universality threatens the account of temporal directionality as well. Various attempts to “exorcise” the Demon, by proving that it is impossible for one reason or another, have been made throughout the years, but none of them were successful. We have shown (in a number of publications) by a general state-space argument that Maxwell’s Demon is compatible with classical mechanics, and that the most recent solutions, based on Landauer’s thesis, are not general. In this paper we demonstrate that Maxwell’s Demon is also compatible with quantum mechanics. We do so by analyzing a particular (but highly idealized) experimental setup and proving that it violates the Second Law. Our discussion is in the framework of standard quantum mechanics; we give two separate arguments in the framework of quantum mechanics with and without the projection postulate. We address in our analysis the connection between measurement and erasure interactions and we show how these notions are applicable in the microscopic quantum mechanical structure. We discuss what might be the quantum mechanical counterpart of the classical notion of “macrostates”, thus explaining why our Quantum Demon setup works not only at the micro level but also at the macro level, properly understood. One implication of our analysis is that the Second Law cannot provide a universal lawlike basis for an account of the arrow of time; this account has to be sought elsewhere.


2021 ◽  
Vol 01 (1) ◽  
pp. 14-18
Author(s):  
Bijan K. Paul ◽  

The present article is motivated toward delving into the concept of entropy, a fundamental consequence of the second law of thermodynamics with particular emphasis on the thought experiment by James C. Maxwell, famously known as the “Maxwell’s demon”, which in turn enables our visualization of the connection of entropy with information.


2019 ◽  
Vol 17 (2) ◽  
pp. 161-171
Author(s):  
Dejan Dimitrijevic

Maxwell's demon is an imaginary being invented a century and a half ago by James Clarke Maxwell in order to illustrate the statistical nature of the Second Law of thermodynamics. It helped us reach a better understanding not only of that law but also of the relationship between statistical physics and thermodynamics. Since the 1910?s it has caused a flood of papers of scientists who have tried to save the Second Law from the threat of the demon and hence preclude the possibility of perpetuum mobile of the second kind. Nowadays, it helps us better understand the possibility of constructing an interactionist model of mental causation manifested through the violation of the Second Law by the mind.


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