Jürg Fröhlich (ETH)
The Arrow of Time - Images of Irreversible Behavior
Abstract:
I sketch various examples of physical systems with time-reversal
invariant dynamics exhibiting irreversible behavior. I start with
deriving the Second Law of Thermodynamics in the formulation of
Clausius from the existence of quantum-mechanical heat baths and
then derive the Carnot bound for the degree of efficiency of heat
engines. I continue with the analysis of a quantum-mechanical
model with unitary time evolution describing a particle that
exhibits diffusive motion when coupled to a suitably chosen
(non-interacting) heat bath. A classical model with a Hamiltonian
time evolution describing a particle coupled to a wave medium
exhibiting friction is sketched next. I conclude with an attempt
to draw the attention of the audience to the fact that the dynamics
of isolated, open quantum systems featuring events is fundamentally
irreversible.