Floquet dynamical phase transition and entanglement spectrum

TL;DR

This paper investigates Floquet dynamical quantum phase transitions in a one-dimensional p-wave superconductor, revealing how they occur in specific frequency ranges and are characterized by entanglement spectrum degeneracies and purity measures.

Contribution

It demonstrates that FDQFTs can occur without quenches, identifies resonance conditions, and shows entanglement spectrum as a tool to detect these transitions.

Findings

FDQFTs occur within specific driving frequency ranges.

Entanglement spectrum degeneracy signals dynamical topological regions.

Purity entanglement measure indicates the boundary of FDQFT occurrence.

Abstract

We explore both pure and mixed states Floquet dynamical quantum phase transitions (FDQFTs) in the one-dimensional p-wave superconductor with a time-driven pairing phase. In the Fourier space, the model is recast to the non-interacting quasi-spins subjected to a time-dependent effective magnetic field. We show that FDQFTs occur within a range of driving frequency without resorting to any quenches. Moreover, FDQFTs appear in the region where quasi-spins are in the resonance regime. In the resonance regime, the population completely cycles the population between the spin down and up states. Additionally, we study the conditions for the appearance of FDQFTs using the entanglement spectrum and purity entanglement measure. Our results imply that the entanglement spectrum can truly capture the resonance regime where FDQFTs occur. Particularly, the dynamical topological region results in the degeneracy of the entanglement spectrum. It is shown that the boundary of the driven frequency range, over which the system reveals FDQFTs, signaled by the purity entanglement measure.