Post quench entropy growth in a chiral clock model

Abstract

We numerically study quenches from a fully ordered state to the ferromagnetic regime of the chiral Z3 clock model, where the physics can be understood in terms of sparse domain wall quasiparticles of six flavors. Similar to the previously studied models, ballistic spread of entangled domain wall pairs generated by the quench lead to a linear growth in entropy upto a time /2vg in size-subsystems in the bulk where vg is the maximal group velocity of domain walls. In small subsystems located in the bulk, entropy continues to further grow towards ln 3, as domain walls that cross the subsystem increment the population of the two oppositely ordered states and restoring the Z3 symmetry. The latter growth in entropy is seen also in small subsystems near an open boundary of the system in a non-chiral clock model. In contrast to this, in the case of the chiral model, entropy of small subsystems near an open boundary of the system saturates. We rationalize the difference in behavior in terms of qualitatively different scattering properties of domain walls at the open boundary in the chiral model. We also present empirical results for entropy growth, correlation spread, and energies of longitudinal-field-induced bound states of domain wall pairs in the chiral model.