In a quantum quench, system is prepared in some initial state (usually the ground state of some hamiltonian) and then allowed evolve in isolation with a different hamiltonian, for example, by rapidly quenching a parameter. This is most interesting for many-body systems where one can ask questions such as whether subsystems reach a stationary state, whether this state appears thermal, and how quickly does it reach this state. Although an obvious set of problems, they have only recently come to the fore with possibility of performing such experiments in ultra-cold atoms and other systems. In this talk I will try to address these questions in the context of some simple, and not-so-simple exactly solvable models.

 

Refreshments will be served in CP 179 at 3:15 PM