Speaker
Alessio Lerose
(TS)
Description
In recent years, the dynamical consequences of spontaneous symmetry breaking have been investigated: What is the fate of the order parameter when the system is driven away from equilibrium?
Mean-field analyses suggest that dynamical criticality sistematically appears. However, they rigorously describe unrealistic infinite-range of infinite-dimensional limits, where few collective macroscopic variables play a role and all the microscopic degrees of freedom, associated with spatial fluctuations, are frozen.
It is a matter of principle to understand whether such dynamical criticality is robust to the inclusion of fluctuations (that are present even at zero temperature in quantum systems): will they be able to drive the system to thermal equilibrium, and hence trivialize the dynamical critical phenomenon into a standard equilibrium transition? If so, the above dynamical criticality would just be a mean-field artifact.
We address this problem by studying an infinite-range Ising model in a transverse field with an additional short-range interaction. I will show a viable systematic approach to deal with the out-of-equilibrium dynamics that goes beyond mean-field.
The results are rather surprising: the spatial fluctuation modes turn out to have a deep impact to the dynamical critical point, giving rise to a whole new region with chaotic features, characterized by an "unpredictable" asymptotic order for long times. The latter non-trivial phenomenon, confirmed by numerical simulations of the exact quantum dynamics, is completely absent at mean-field level.
Primary author
Alessio Lerose
(TS)
Co-authors
Prof.
Alessandro Silva
(SISSA, Trieste)
Prof.
Andrea Gambassi
(SISSA, Trieste)
Dr
Bojan Zunkovic
(Univ. Ljubljana)
Dr
Jamir Marino
(JILA, Boulder)
