Abstract
We investigate the effects of fluctuations on the dynamics of an isolated quantum system represented by a field theory with symmetry after a quench in spatial dimensions. A perturbative renormalization-group approach involving a dimensional expansion in is employed in order to study the evolution within a prethermal regime controlled by elastic dephasing. In particular, we focus on a quench from a disordered initial state to the critical point, which introduces an effective temporal boundary in the evolution. At this boundary, the relevant fields acquire an anomalous scaling dimension, while the evolution of both the order parameter and its correlation and response functions display universal aging. Since the relevant excitations propagate ballistically, a light cone in real space emerges. At longer times, the onset of inelastic scattering appears as secularly growing self-generated dissipation in the effective Keldysh field theory, with the strength of the dissipative vertices providing an estimate for the time needed to leave the prethermal regime.
- Received 15 April 2016
- Revised 2 September 2016
DOI:https://doi.org/10.1103/PhysRevB.94.134311
©2016 American Physical Society