Entanglement signatures of quantum criticality in Floquet non-Hermitian topological systems

TL;DR

This paper demonstrates that entanglement entropy effectively detects topological phase transitions in Floquet non-Hermitian systems, revealing universal features and spectral signatures that distinguish different phases.

Contribution

It introduces entanglement entropy as a robust diagnostic tool for topological transitions in driven non-Hermitian systems, including complex spectral features and phase diagram construction.

Findings

Entanglement entropy peaks at phase transitions with logarithmic scaling.

Entanglement spectrum distinguishes topological phases and hybridization effects.

Results are robust in non-Hermitian regimes and with next-nearest-neighbor hopping.

Abstract

The entanglement entropy can be an effective diagnostic tool for probing topological phase transitions. In one-dimensional single particle systems, the periodic driving generates a variety of topological phases and edge modes. In this work, we investigate the topological phase transition of the one-dimensional Floquet Su-Schrieffer-Heeger model using entanglement entropy, and construct the phase diagram based on entanglement entropy. The entanglement entropy exhibits pronounced peaks and follows the logarithmic scaling law at the phase transition points, from which we extract the central charge $c=1$. We further investigate the entanglement spectrum to accurately distinguish the different topological phases. In addition, the coupling between zero and $\pi$ modes leads to characteristic splittings in the entanglement spectrum, signaling their hybridization under periodic driving. These results remain robust in non-Hermitian regimes and in the presence of next-nearest-neighbor hopping, demonstrating the reliability and universality of entanglement entropy as a diagnostic for topological phase transitions.