Dynamical Quantum Phase Transitions in Extended Transverse Ising Models

TL;DR

This paper investigates how extended interactions in a transverse Ising model influence dynamical quantum phase transitions, revealing unusual behaviors such as non-changing winding numbers and degenerate critical modes.

Contribution

It uncovers novel effects of extended interactions on DQPTs, including cases where winding numbers do not change and multiple critical modes degenerate into a single mode.

Findings

Winding number may not change across a gap closing in some cases.

Extended interactions can lead to degenerate critical modes.

In the cluster Ising limit, three critical modes become degenerate.

Abstract

We study the dynamical quantum phase transitions (DQPTs) manifested in the subsequent unitary dynamics of an extended Ising model with additional three spin interactions following a sudden quench. Revisiting the equilibrium phase diagram of the model where different quantum phases are characterised by different winding numbers, we show that in some situations the winding number may not change across a gap closing point in the energy spectrum. Although, usually there exists a one-to-one correspondence between the change in winding number and the number of critical time scales associated with DQPTs, we show that the extended nature of interactions may lead to unusual situations. Importantly, we show that in the limit of the cluster Ising model, three critical modes associated with DQPTs become degenerate and thereby leading to a single critical time scale for a given sector of Fisher zeros.