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?



closed as too broad by user10851, Emilio Pisanty, Waffle's Crazy Peanut, tpg2114, akhmeteli Nov 1 '13 at 2:38

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Related: physics.stackexchange.com/q/39457/2451 $\endgroup$ – Qmechanic Oct 26 '13 at 23:55
  • 2
    $\begingroup$ 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 '13 at 1:40
  • 4
    $\begingroup$ 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 Brown Oct 28 '13 at 1:51
  • 1
    $\begingroup$ What is the actual question here? Is there something specific that you find confusing? $\endgroup$ – Colin McFaul Oct 29 '13 at 17:54