Dynamical quantum phase transitions in a spin chain with deconfined quantum critical points

TL;DR

This paper investigates dynamical quantum phase transitions in a spin chain with deconfined quantum critical points, revealing that such transitions can occur between broken symmetry phases and are not solely tied to equilibrium phase transitions.

Contribution

It provides an analytical and numerical study of Loschmidt echo and order parameters in a spin chain with deconfined criticality, including exact mappings and quench dynamics analysis.

Findings

Dynamical quantum phase transitions occur between dimerized and ferromagnetic phases.

Exact mapping to classical Ising chain for specific quenches.

Fast relaxation prevents long-term dynamical transitions in some cases.

Abstract

We analytically and numerically study the Loschmidt echo and the dynamical order parameters in a spin chain with a deconfined phase transition between a dimerized state and a ferromagnetic phase. For quenches from a dimerized state to a ferromagnetic phase, we find that the model can exhibit a dynamical quantum phase transition characterized by an associating dimerized order parameters. In particular, when quenching the system from the Majumdar-Ghosh state to the ferromagnetic Ising state, we find an exact mapping into the classical Ising chain for a quench from the paramagnetic phase to the classical Ising phase by analytically calculating the Loschmidt echo and the dynamical order parameters. By contrast, for quenches from a ferromagnetic state to a dimerized state, the system relaxes very fast so that the dynamical quantum transition may only exist in a short time scale. We reveal that the dynamical quantum phase transition can occur in systems with two broken symmetry phases and the quench dynamics may be independent on equilibrium phase transitions.