Thermalization dynamics of quantum spin chains

3 06/2013

Monday, 03 Jun. 2013, 14:00 - 15:00

Presenter: Jamir MARINO, SISSA - International School for Advanced Studies, Trieste
Host: J. Schmiedmayer
Where: Atominstitut Seminarraum, Stadionallee 2, 1020 Wien

In the last decade the impressive progress in manipulating cold atoms stimulated theoretical research on non-equilibrium dynamics of quantum many body systems. While in the past few years a great deal of attention has been paid to the description of the asymptotic steady state, much less is known about the dynamics of equilibration of both thermally isolated and open quantum many-body systems. For closed systems recent studies suggest that the system decays first to the so-called pre-thermalized state, and only at a second stage real thermalization occurs. In the first part of this talk I will present the dynamics of thermalization resulting from a time-dependent noise in a Quantum Ising Chain subject to a sudden quench of the transverse magnetic field, showing that pre-thermalization can occur even in noisy systems driven out of equilibrium, while, in the second part, I will consider the more involved case of the composite quench of a Quantum Ising Chain whose integrability is broken by the (sudden) introduction of a long-range interaction. Within the Keldysh formalism, I will show which are the diagrams responsible for pre-thermalization and thermalization, and, mapping this system into an hard core boson chain, I will describe how the system relaxes towards the pre-thermal state.