Does Third Law of thermodynamics violates Quantum Mechanics, I mean Why third law of Thermodynamics holds if we think about it in terms of Quantum Mechanics ?

  • $\begingroup$ Can you be more specific?why should 3rd law of thermodynamics violate quantum mechanics? $\endgroup$
    – Paul
    Mar 5, 2015 at 5:20
  • $\begingroup$ I am not saying that it violates quantum mechanics, but I am just wondering why third law of thermodynamics holds in terms of Quantum Mechanics like (degeneracy....) $\endgroup$ Mar 5, 2015 at 5:32
  • 1
    $\begingroup$ Note the caveat here, "and this statement of the third law holds true if the perfect crystal has only one minimum energy state." $\endgroup$
    – lemon
    Mar 5, 2015 at 8:17
  • $\begingroup$ Somebody told me, that for a system with a large number of degree of freedom, the third law of entropy should be $Lim_{T\rightarrow 0, N\rightarrow \infty} S/N=0$. I am not sure about the order of the limits though. $\endgroup$ Dec 29, 2017 at 15:49

1 Answer 1


Even without quantum mechanics, the third law of thermodynamics only holds if there is a single lowest-energy state. For example, if there are two degenerate lowest-energy states, then the entropy is $k_B \log2$.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.