Theoretical investigation of dynamics and concurrence of entangled PT and anti-PT symmetric polarized photons

Non-Hermitian systems with parity-time (PT) symmetry and anti-parity-time (APT) symmetry have exceptional points (EPs) resulting from eigenvector co-coalescence with exceptional properties. In the quantum and classical domains, higher-order EPs for PT symmetry and APT-symmetry systems have been proposed and realized. Both two-qubits APT-APT and PT-PT symmetric systems have seen an increase in recent years, especially in the dynamics of quantum entanglement. However, to our knowledge, neither theoretical nor experimental investigations have been conducted for the dynamics of two-qubits entanglement in the PT-APT symmetric system. We investigate the PT-APT dynamics for the first time. Moreover, we examine the impact of different initial Bell-state conditions on entanglement dynamics in PT-PT, APT-APT and PT-APT symmetric systems. Additionally, we conduct a comparative study of entanglement dynamics in the PT-PT symmetrical system, APT-APT symmetrical system, and PT-APT symmetrical systems in order to learn more about non-Hermitian quantum systems and their environments. Entangled qubits evolve in a PT-APT symmetric unbroken regime, the entanglement oscillates with two different oscillation frequencies, and the entanglement is well preserved for a long period of time for the case when non-Hermitian parts of both qubits are taken quite away from the exceptional points.

Automated summary

In this study, we investigate the dynamics of entanglement in a PT-APT symmetric system for the first time. We also compare the entanglement dynamics in PT-PT symmetric systems, APT-APT symmetric systems, and PT-APT symmetric systems to gain further insights into non-Hermitian quantum systems and their environments. Our findings show that in the unbroken regime of the PT-APT symmetric system, entanglement oscillates with two different frequencies and can be well preserved for a long time when the non-Hermitian parts of the qubits are far from the exceptional points.