Liouville & Entropy: Solving the Controversy

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The discussion centers on the perceived conflict between the second law of thermodynamics and Liouville's theorem, particularly regarding the behavior of gas molecules over time. It argues that while the second law suggests entropy should always increase, in reality, fluctuations can occur, allowing for temporary decreases in entropy. This implies that the second law is a statistical result rather than an absolute rule, and significant deviations could theoretically happen over extremely long timescales. References to the fluctuation theorem and experimental evidence of temporary entropy decreases support this view. Overall, the conversation highlights the complexity of thermodynamic laws in real systems.
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Next to all recent Entropy thread I'd also like to have a question solved.

What's the solution to the controversy between the second law of thermodynamics, and Liouville's theorem that for conservative systems (as a gas should be?!) every state should be reached at some point? So eventually after an extraordinary long time all molecules would also gather in the corner.
 
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I don't think there is a controversy. The strict "thermodynamic" result is
only valid for an infinite number of particles (thus, no fluctuations). Real
systems do fluctuate though; all particles gathering in one place would be
a BIG fluctuation, thus very low probability, thus something that would only
happen after a very, very long time.
 
OK, that's also my favourite interpretation.

So the second law is rather a statistical result and in an extremely long period of time the second law could be arbitrarily violated?!

Any objections from someone else?
 
Gerenuk said:
OK, that's also my favourite interpretation.

So the second law is rather a statistical result and in an extremely long period of time the second law could be arbitrarily violated?!

Any objections from someone else?

You're right. I've posted a few questions of the same kind. For instance, see https://www.physicsforums.com/showthread.php?t=319633.
See the fluctuation theorem. There was a paper about an experiment that showed entropy decreases macroscopically for a few seconds... The paper was accessible from wikipedia. The Second Law is not a "fundamental law".
I just found something related to the article: http://www.newscientist.com/article/dn2572-second-law-of-thermodynamics-broken.html.
 
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