2 Dec 2025 Tue 4 pm

Motivated by a great success of implementation PT-symmetry in non-Hermitian photonic systems [1], and recent experiments on single non-Hermitian superconducting qubits [2-4], ultracold atoms [4], and spin-qubits [5], I present here a theoretical analysis of an exemplary PT-symmetric non-Hermitian arrays of interacting qubits described by spin interacting models. A non-Hermitian part of the Hamiltonian will be implemented via imaginary staggered longitudinal magnetic field, which corresponds to a local staggered gain and loss terms. I will show that combining non-Hermiticity and interactions in PT-symmetric non-Hermitian arrays of interacting qubits gives rise to a plethora of intriguing physical phenomena, allows to identify novel collective quantum phases and excitations, e.g., PT-symmetry broken and unbroken regimes of collective (anti)ferromagnetic states in the Ising model, paramagnetic and compressible superfluid states in XX spin models [6]. I will also explore an opportunity to realize the procedure of quantum annealing, i.e., quantum dynamics with adiabatic variation of Hamiltonian parameters, in PT-symmetric non-Hermitian quantum networks of interacting qubits.

References

[1] Ramy El-Ganainy, et al., Nature Physics, 14, 11 (2018).

[2] M. Naghiloo, et al., Nature Physics 15, 1232 (2019).

[3] Sh. Dogra, et al., Communications Physics 4, 26 (2021).

[4] A. S. Kazmina et al., Phys. Rev. A 109, 032619 (2024).

[5] Y. Wu, et al., Science 364, 878 (2019).

[6] L. Tetling, M. V. Fistul, and I. M. Eremin, Phys. Rev. B 106, 134511 (2022); G. A. Starkov, M. V. Fistul, and I. M. Eremin, Physical Review A 108, 022206 (2023); G. A. Starkov, M. V. Fistul, and I. M. Eremin, Annals of Physics 456, 169268 (2023); G. A. Starkov, M. V. Fistul, and I. M. Eremin, Phys. Rev. B 108, 235417,(2023).

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