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arXiv · 2507.03768

Entanglement transitions in structured and random nonunitary Gaussian circuits

Bastien Lapierre·Liang-Hong Mo·Shinsei Ryu
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Abstract

We study measurement-induced phase transitions in quantum circuits consisting of kicked Ising models with postselected weak measurements, whose dynamics can be mapped onto a classical dynamical system. For a periodic (Floquet) non-unitary evolution, such circuits are exactly tractable and admit volume-to-area law transitions. We show that breaking time-translation symmetry down to a quasiperiodic (Fibonacci) time evolution leads to the emergence of a critical phase with tunable effective central charge and with a fractal origin. Furthermore, for some classes of random non-unitary circuits, we demonstrate the robustness of the volume-to-area law phase transition for arbitrary random realizations, thanks to the emergent compactness of the classical map encoding the circuit's dynamics.

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Bastien Lapierre, Liang-Hong Mo, Shinsei Ryu. 2025-07-04. Entanglement transitions in structured and random nonunitary Gaussian circuits. https://arxiv.org/abs/2507.03768

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