Can statistical mechanics be reduced to classical or quantum mechanics?

by Prof. Barbara Drossel (TU Darmstadt)

Thursday 12 Jun 2025, 16:15 → 17:30 Europe/Berlin

ENC-D114 (ENC)

The microscopic description of many-particle systems via Newtons equations of motion or the Schrödinger equation is deterministic and time reversal invariant. In contrast, the formalism of statistical mechanics suggest irreversible and stochastic behavior on the microscopic scale, and from such a description the  second law of thermodynamics follows naturally. Nevertheless, it is widely assumed that thermodynamics and statistical mechanics can in principle be derived from classical mechanics or quantum mechanics.  Such derivations usually invoke our ignorance of microscopic details of the system. This talk will show that in fact these supposed derivations require additional assumptions that go beyond Newton's equations or the Schrödinger equation.  I will argue that we have to give up the notion that classical mechanics and quantum mechanics are a description that is infinitely exact (i.e., uses an infinite number of bits). Then statistical mechanics and thermodynamics follow naturally.