Entanglement transitions in structured and random nonunitary Gaussian circuits
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.
Cite
@article{arxiv.2507.03768,
title = {Entanglement transitions in structured and random nonunitary Gaussian circuits},
author = {Bastien Lapierre and Liang-Hong Mo and Shinsei Ryu},
journal= {arXiv preprint arXiv:2507.03768},
year = {2025}
}