Theoretical challenges to the 2nd Law?

What are some the theoretical challenges to the 2nd Law?

(cf. Čápek, Vladislav, and Daniel P. Sheehan. Challenges to the Second Law of Thermodynamics: Theory and Experiment. Springer, 2005., chapter "Modern Quantum Challenges: Theory.")

Experimental challenges to the 2nd Law?

Is there an experiment that has found violations of the 2nd Law of Thermodynamics? Is there an experiment that shows that entropy decreases for certain systems?


  • $\begingroup$ Related: physics.stackexchange.com/q/39457/2451 $\endgroup$
    – Qmechanic
    Oct 26, 2013 at 23:55
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    $\begingroup$ Since thermodynamics describes the behavior of large number of particles, there is no reason for few-body systems in QM obey the 2nd law. Maybe i am just stupid ... $\endgroup$
    – user26143
    Oct 28, 2013 at 1:40
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    $\begingroup$ Entropy has everything to do with coarse graining and the thermodynamic limit and nothing to do with quantum vs. classical mechanics. Spontaneous entropy decrease happens even in classical systems if you wait long enough. (Though note that for macroscopic systems you have to wait a long time.) $\endgroup$
    – Michael
    Oct 28, 2013 at 1:51
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    $\begingroup$ What is the actual question here? Is there something specific that you find confusing? $\endgroup$ Oct 29, 2013 at 17:54