English

Classical mechanics as the high-entropy limit of quantum mechanics

Quantum Physics 2026-02-03 v3

Abstract

We show that classical mechanics can be recovered as the high-entropy limit of quantum mechanics. That is, the high entropy masks quantum effects, and mixed states of high enough entropy can be approximated with classical distributions. The mathematical limit 0\hbar \to 0 can be reinterpreted as setting the zero entropy of pure states to -\infty, in the same way that non-relativistic mechanics can be recovered mathematically with cc \to \infty. Physically, these limits are more appropriately defined as S0S \gg 0 and vcv \ll c. Both limits can then be understood as approximations independently of what circumstances allow those approximations to be valid. Consequently, the limit presented is independent of possible underlying mechanisms and of what interpretation is chosen for both quantum states and entropy.

Keywords

Cite

@article{arxiv.2411.00972,
  title  = {Classical mechanics as the high-entropy limit of quantum mechanics},
  author = {Gabriele Carcassi and Manuele Landini and Christine A. Aidala},
  journal= {arXiv preprint arXiv:2411.00972},
  year   = {2026}
}

Comments

16 pages, 4 figures. Version accepted by Physica Scripta