Physical
Loschmidt's Paradox (Reversibility Paradox)
How does irreversible thermodynamics arise from reversible mechanics?
Overview
The puzzle of how time-irreversible thermodynamics emerges from time-reversible microscopic laws.
Newton's laws and quantum mechanics are time-reversible (work equally forward and backward in time). Yet thermodynamics is irreversible (entropy increases, eggs don't unscramble). How does irreversibility emerge from reversible laws?