2025-06-19 東京大学
量子測定によって誘起されるトポロジカル相の概念図
<関連情報>
- https://www.t.u-tokyo.ac.jp/press/pr2025-06-19-002
- https://www.t.u-tokyo.ac.jp/hubfs/press-release/2025/0619/002/text.pdf
- https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.240401
測定誘起相転移におけるトポロジーとスペクトル Topology and Spectrum in Measurement-Induced Phase Transitions
Hisanori Oshima, Ken Mochizuki, Ryusuke Hamazaki, and Yohei Fuji
Physical Review Letters Published: 18 June, 2025
DOI: https://doi.org/10.1103/PhysRevLett.134.240401
Abstract
Competition among repetitive measurements of noncommuting observables and unitary dynamics can give rise to a wide variety of entanglement phases. Here, we propose a general framework based on Lyapunov analysis to characterize topological properties in monitored quantum systems through their spectrum and many-body topological invariants. We illustrate this framework by analyzing (1+1)-dimensional monitored circuits for Majorana fermions, which are known to exhibit topological and trivial area-law entangled phases as well as a critical phase with sub-volume-law entanglement. Through the Lyapunov analysis, we identify the presence (absence) of edge-localized zero modes inside the bulk gap in the topological (trivial) phase and a bulk gapless spectrum in the critical phase. Furthermore, by suitably exploiting the fermion parity with twisted measurement outcomes at the boundary, we construct a topological invariant that distinguishes the two area-law phases and dynamically characterizes the critical phase. Our framework thus provides a general route to extend the notion of bulk-edge correspondence to monitored quantum dynamics.