Seminario Filiberto Ares (SISSA, Trieste, Italia)

"Entanglement asymmetry and the quantum Mpemba effect"

Filiberto Ares,

(SISSA, Trieste, Italia)

Abstract:

The Mpemba effect is the counterintuitive and controversial phenomenon
that hot water can cool faster than cold one, or in more formal words,
the more a system is out of equilibrium, the faster it relaxes. In
this talk, we introduce an analogous effect in extended quantum
systems, in which a symmetry explicitly broken by the initial state is
dynamically restored by the time evolution after a quantum
quench. Unexpectedly, we find that the more the symmetry is initially
broken, the faster is restored. To study this phenomenon, we borrow
methods from the theory of entanglement in many-body systems and we
introduce a new quantity, dubbed entanglement asymmetry, which
measures how much a symmetry is broken in a subsystem. The quantum
Mpemba effect is not as controversial as its classical version since
it is well supported by analytic calculations in free systems, exact
numerical results in (non)-integrable interacting spin chains, and is
observable in ion-trap experiments.

Fecha: Jueves 7 de septiembre, 12:10, seminario de Física Teórica.