Quantum Quenches in Integrable Field Theories

Understand

We study the non equilibrium time evolution of an integrable field theory in 1+1 dimensions after a sudden variation of a global parameter of the Hamiltonian.

• For a class of quenches defined in the text, we compute the long times limit of the one point function of a local operator as a series of form factors.
• Even if some subtleties force us to handle this result with care, there is a strong evidence that for long times the expectation value of any local operator can be described by a generalized Gibbs ensemble with a different effective temperature for each eigenmode.