Loschmidts Paradox

Loschmidt s paradox states that if there is a motion of a system that leads to a steady increase of entropy with time, then there is certainly another allowed state of motion of the system, found by time reversal, in which the entropy must decrease. 

The principle of time reversal is well established in mechanics, as the second law of thermodynamics is well established in thermodynamics. By Loschmidt s considerations, both principles are opposed in a conflicting way. 

The paradox can be resolved in assuming that in cosmology there is an arrow of time. On the other hand, by fluctuations, the second law of thermodynamics may be violated [14]. 

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Loschmidt Paradox. /( )=/(— ) mirrors the reversibility, and this is evidently compatible with an approach to equilibrium. 

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