Ehrenfest’s Theorem revisited

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Henryk Stanisław Arodź


Historically, Ehrenfest’s theorem (1927) is the first one which shows that classical physics can emerge from quantum physics as a kind of approximation. We recall the theorem in its original form, and we highlight its generalizations to the relativistic Dirac particle and to a particle with spin and izospin. We argue that apparent classicality of the macroscopic world can probably be explained within the framework of standard quantum mechanics.

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Arodź, H. S. (2019). Ehrenfest’s Theorem revisited. Philosophical Problems in Science (Zagadnienia Filozoficzne W Nauce), (66), 73–94. Retrieved from
Emergence of the Classical


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