講演題目: Simulating non-Hermitian many-body quench dynamics on superconducting quantum processors
講師: 高橋 雅大 氏
日時: 2026年11月2日(月) 13:30 – 15:30
場所: 北海道大学工学部 C325
要旨:
Recent advances in programmable quantum processors have enabled experimental studies of quantum many-body dynamics, as demonstrated in recent large-scale experiments [1]. While unitary Hamiltonian dynamics can be naturally implemented using quantum circuits, simulating open quantum systems remains challenging because their dynamics are generally nonunitary. Developing practical approaches to realize such dynamics and demonstrating them on actual quantum processors are therefore important steps toward extending the scope of digital quantum simulation.
In this seminar, I will present our experimental simulation of non-Hermitian many-body dynamics on a superconducting quantum processor [2]. We consider the Yang–Lee model, a transverse-field Ising model subject to an imaginary longitudinal field, and implement its nonunitary time evolution through unitary dilation with ancillary qubits and postselection [3, 4]. We investigate quench dynamics across the PT-symmetry-breaking transition and observe qualitatively distinct dynamical behavior in the PT-unbroken and PT-broken regimes. We further study the spreading of two-point correlations and find signatures of supersonic propagation beyond the maximum quasiparticle group velocity [5, 6].
I will also talk about our recent implementation of Markovian quantum dynamics using quantum collision models on trapped-ion and superconducting quantum processors [7], where interactions with ancillary qubits are used to realize dissipative processes. Together, these studies illustrate different routes toward extending digital quantum simulation from closed systems to open and non-Hermitian quantum many-body dynamics.
[1] For example, E. Leviatan et al., arXiv:2607.24937 (2026).
[2] MOT, Z. Wang, A. Bhardwaj, & S. Yunoki in preparation.
[3] S.-H. Lin, R. Dilip, A. G. Green, A. Smith & F. Pollmann, Phys. Rev. X Quantum 2, 010342 (2021).
[4] R. Shen, T. Chen, B. Yang, & C. H. Lee, Nat. Commun. 16, 1340 (2025).
[5] Y. Ashida & M. Ueda, Phys. Rev. Lett. 120, 185301 (2018).
[6] Y. Zhang, J. Carrasquilla, & Y. B. Kim, Nat. Comm. 16, 3286 (2025).
[7] Z. Wang, J. D. Teske, A. Bhardwaj, MOT, & S. Yunoki, arXiv:2606.27856.