Prethermalization: Quantum and dynamical universality in quench dynamics

A long-lived prethermal state may emerge upon a sudden quench of a quantum system. In this talk, I consider a quantum quench of an initial critical state, and show that the resulting prethermal state exhibits a genuinely quantum and dynamical universal behavior. Specifically, I consider a scenario where the “speed of light” characterizing the propagation of local perturbations is suddenly quenched at criticality. I also briefly discuss how the system approaches the prethermal state in a universal way described by a new exponent that characterizes a kind of quantum aging.