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arXiv · 2403.13435

Measurement-only dynamical phase transition of topological and boundary order in toric code and gauge-Higgs models

Takahiro Orito·Yoshihito Kuno·Ikuo Ichinose
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Abstract

We extensively study long-time dynamics and fate of topologically-ordered state in toric code model evolving through projective measurement-only circuit. The circuit is composed of several measurement operators corresponding to each term of toric code Hamiltonian with magnetic-field perturbations, which is a gauge-fixed version of a (2+1)-dimensional gauge-Higgs model. We employ a cylinder geometry with distinct upper and lower boundaries to classify stationary states after long-time measurement dynamics. The appearing stationary states depend on measurement probabilities for each measurement operator. The Higgs, confined and deconfined phases emerge in the time evolution by the circuit. We find that both Higgs and confined phases are separated from the deconfined phase by topological entanglement entropy. We numerically clarify that both Higgs and confined phases are characterized by a long-range order on the boundaries accompanying edge modes, and they shift with each other by a crossover reflecting properties in the bulk phase diagram.

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Takahiro Orito, Yoshihito Kuno, Ikuo Ichinose. 2024-06-02. Measurement-only dynamical phase transition of topological and boundary order in toric code and gauge-Higgs models. https://doi.org/10.1103/physrevb.109.224306

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