Dynamical topological transitions in the massive Schwinger model with a {\theta}-term

TL;DR

This paper investigates real-time topological phase transitions in the massive Schwinger model with a θ-term, revealing dynamical quantum phase transitions and a topological order parameter applicable to interacting theories, with implications for quantum simulation.

Contribution

It introduces a dynamical topological order parameter for the massive Schwinger model, demonstrating persistent topological transitions beyond weak coupling and linking theory to feasible quantum simulation experiments.

Findings

Identification of dynamical quantum phase transitions between topological sectors.

Development of a general dynamical topological order parameter accessible via fermion correlators.

Persistence of topological transitions beyond weak-coupling regime.

Abstract

Aiming at a better understanding of anomalous and topological effects in gauge theories out-of-equilibrium, we study the real-time dynamics of a prototype model for CP-violation, the massive Schwinger model with a $\theta$-term. We identify dynamical quantum phase transitions between different topological sectors that appear after sufficiently strong quenches of the $\theta$-parameter. Moreover, we establish a general dynamical topological order parameter, which can be accessed through fermion two-point correlators and, importantly, which can be applied for interacting theories. Enabled by this result, we show that the topological transitions persist beyond the weak-coupling regime. Finally, these effects can be observed with table-top experiments based on existing cold-atom, superconducting-qubit, and trapped-ion technology. Our work, thus, presents a significant step towards quantum simulating topological and anomalous real-time phenomena relevant to nuclear and high-energy physics.