Phase boundaries in alternating field quantum XY model with Dzyaloshinskii-Moriya interaction: Sustainable entanglement in dynamics

TL;DR

This paper maps the phase diagram of the quantum XY model with Dzyaloshinskii-Moriya interaction and magnetic fields, revealing new phases and entanglement properties, including a chiral phase and sustainable entanglement dynamics.

Contribution

It introduces the effects of Dzyaloshinskii-Moriya interaction on phase boundaries and entanglement in the XY model with uniform and alternating magnetic fields, identifying a new chiral phase and entanglement behavior.

Findings

DM interaction weaker than anisotropy has no effect on zero-temperature states with uniform field

A new gapless chiral phase appears when DM interaction exceeds anisotropy

DM interaction enables sustainable bipartite entanglement at large times

Abstract

We report all phases and corresponding critical lines of the quantum anisotropic transverse XY model with Dzyaloshinskii-Moriya (DM) interaction along with uniform and alternating transverse magnetic fields (ATXY) by using appropriately chosen order parameters. We prove that when DM interaction is weaker than the anisotropy parameter, it has no effect at all on the zero-temperature states of the XY model with uniform transverse magnetic field which is not the case for the ATXY model. However, when DM interaction is stronger than the anisotropy parameter, we show appearance of a new gapless phase - a chiral phase - in the XY model with uniform as well as alternating field. We further report that first derivatives of nearest neighbor two-site entanglement with respect to magnetic fields can detect all the critical lines present in the system. We also observe that the factorization surface at zero-temperature present in this model without DM interaction becomes a volume on the introduction of the later. We find that DM interaction can generate bipartite entanglement sustainable at large times, leading to a proof of ergodic nature of bipartite entanglement in this system, and can induce a transition from non-monotonicity of entanglement with temperature to a monotonic one.