Three entangled photon dynamics in PT- and anti-PT-symmetric systems

Muhammad Abid, Areeda Ayoub, Javed Akram

Yadi Niu, Xinchen Zhang, Nuo Wang +2 more

In this research, we study the coherent perfect absorption (CPA) induced entanglement in Anti-PT symmetric three-waveguide system. The quantum Anti-PT phase diagram of the three-waveguide system is obtained. Based on the phase diagram, we calculated the transmission spectrum of the system in Anti-PT symmetric phase to demonstrate its CPA behavior. Finally, the output entanglement negativity of a separable input state is investigated. Non-zero negativity shows that entanglement is generated and protected by CPA against dissipation in the system. Our research prompts the study on quantum Anti-PT symmetric system and quantum CPA, and may have potentials in integrated quantum information processing.

Ahmadi, Amir, Asgari, Roozbeh H., Javad T. Firouzjaee

In this study, we investigate qubit dynamics under PT and Anti-PT-symmetric non-Hermitian Hamiltonians, focusing on phase evolution, decoherence, quantum speed limits (QSL), and Rényi entanglement entropies. Using similarity transformations and Dyson maps, we analyze the reduced density matrix evolution in bosonic environments. Anti-PT-symmetric systems show enhanced robustness against decoherence, with slower entropy growth and longer coherence times compared to PT-symmetric counterparts. QSL behavior is non-monotonic, reflecting rapid initial evolution followed by a gradual decrease. Higher-order Rényi entropies reveal that Anti-PT-symmetric qubits preserve quantum information more effectively, offering advantages for memory and cryptographic applications.

Eva-Maria Graefe

Ya-Wei Zeng, Wei-Xin Chen, Tian-Le Yang +2 more

We propose a scheme for enhanced sensing of weak anharmonicities based on a three-mode anti-parity-time (anti-PT) symmetric cavity-magnon-waveguide system. By tuning the optical gain to the active cavity mode, the linewidth suppression point for the anti-PT symmetric Hamiltonian can be flexibly controlled even when the two dissipative magnonic modes experience strong intrinsic decay. This essential characteristic is utilized for detecting weak nonlinearities in both the cavity and magnonic modes, with both demonstrating similar high levels of sensitivity. Moreover, the sensitivity can be greatly improved with a detuned laser drive. Based on the integrated passive-active three-mode anti-PT symmetric system, the sensing scheme can be generalized to various physical systems with anharmonicities.

Phillip F. Schewe