On the Eigenstate Thermalization Hypothesis
Time: Mon 2018-11-12 14.00 - 14.45
Lecturer: Jens Bardarson
Location: FA32, Albanova Universitetscentrum, Roslagstullsbacken 21, Stockholm
Equilibration is the process by which a system reaches a steady state that can be described by statistical mechanics. At first sight, fully coherent quantum dynamics does not seem to be compatible with such thermalization, since the quantum dynamics is unitary and the state of the system is described by a pure density matrix at all times. Nevertheless, in both experiments and simulations, such thermalization is generically observed to quickly take place. How can this be? In this talk I will discuss and explain how such questions are readily and convincingly answered within the framework of the eigenstate thermalization hypothesis. I will review briefly its history and origins in random matrix theory and quantum chaos, before motivating its mathematical expression in terms of matrix elements in the eigenstate basis. Finally, I will mention the few known general situations where the eigenstate thermalization hypothesis is known to fail.