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Dynamical quantum phase transitions, encompassing phenomena like many-body localization transitions and measurement-induced phase transitions, are often characterized and identified through the analysis of quantum entanglement. Here, we…

Quantum Physics · Physics 2024-10-15 Wei Xia , Jie Zou , Xiaopeng Li

The dynamics of monitored systems can exhibit a measurement-induced phase transition (MIPT) between entangling and disentangling phases, tuned by the measurement rate. When the dynamics obeys a continuous symmetry, the entangling phase…

Quantum Physics · Physics 2025-04-09 Xiaozhou Feng , Nadezhda Fishchenko , Sarang Gopalakrishnan , Matteo Ippoliti

The rise of programmable quantum devices has motivated the exploration of circuit models which could realize novel physics. A promising candidate is a class of hybrid circuits, where entangling unitary dynamics compete with disentangling…

Quantum Physics · Physics 2021-12-08 Stefanie Czischek , Giacomo Torlai , Sayonee Ray , Rajibul Islam , Roger G. Melko

We identify an unconventional algebraic scaling phase in the quantum dynamics of free fermions with long range hopping, which are exposed to continuous local density measurements. The unconventional phase is characterized by an algebraic…

Statistical Mechanics · Physics 2022-01-19 Thomas Müller , Sebastian Diehl , Michael Buchhold

We study critical properties of the entanglement and charge-sharpening measurement-induced phase transitions in a non-unitary quantum circuit evolving with a U(1) conserved charge. Our numerical estimation of the critical properties of the…

Disordered Systems and Neural Networks · Physics 2024-11-15 Ahana Chakraborty , Kun Chen , Aidan Zabalo , Justin H. Wilson , J. H. Pixley

Recently, the dynamics of quantum systems that involve both unitary evolution and quantum measurements have attracted attention due to the exotic phenomenon of measurement-induced phase transitions. The latter refers to a sudden change in a…

Quantum Physics · Physics 2025-06-23 Ryotaro Suzuki , Jonas Haferkamp , Jens Eisert , Philippe Faist

We develop a general framework for classifying fermionic dynamical systems with measurements using symmetry and topology. We introduce two complementary classification schemes based on the Altland-Zirnbauer tenfold way: (1) the many-body…

Quantum Physics · Physics 2026-05-25 Asadullah Bhuiyan , Haining Pan , Chao-Ming Jian

Discrete quantum trajectories of systems under random unitary gates and projective measurements have been shown to feature transitions in the entanglement scaling that are not encoded in the density matrix. In this paper, we study the…

Disordered Systems and Neural Networks · Physics 2020-09-24 Nicolai Lang , Hans Peter Büchler

Measurement-induced phase transitions are nonequilibrium transitions between phases characterized by distinct entanglement scaling behaviors, driven by the competition between unitary dynamics and measurements. Despite recent numerical…

Statistical Mechanics · Physics 2026-05-08 Yunxiang Liao , Max Matheussen , Xinghai Zhang

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…

Quantum Physics · Physics 2025-06-24 Hisanori Oshima , Ken Mochizuki , Ryusuke Hamazaki , Yohei Fuji

When subject to a non-local unitary evolution, qubits in a quantum circuit become increasingly entangled. Conversely, measurements applied to individual qubits lead to their disentanglement from the collective system. The extent of…

Quantum Physics · Physics 2025-01-22 Sourav Manna , Vaibhav Madhok , Arul Lakshminarayan

Conformal field theories in curved backgrounds have been used to describe inhomogeneous one-dimensional systems, such as quantum gases in trapping potentials and non-equilibrium spin chains. This approach provided, in a elegant and simple…

Statistical Mechanics · Physics 2019-03-26 Sara Murciano , Paola Ruggiero , Pasquale Calabrese

Non-unitary evolution can give rise to novel steady states classified by their entanglement properties. In this work, we aim to understand its interplay with long-range hopping that decays with $r^{-\alpha}$ in free-fermion systems. We…

Strongly Correlated Electrons · Physics 2022-06-01 Pengfei Zhang , Chunxiao Liu , Shao-Kai Jian , Xiao Chen

Recently there has been an intense effort to understand measurement induced transitions, but we still lack a good understanding of non-Markovian effects on these phenomena. To that end, we consider two coupled chains of free fermions, one…

Quantum Physics · Physics 2024-03-18 Mikheil Tsitsishvili , Dario Poletti , Marcello Dalmonte , Giuliano Chiriacò

We formulate a semi-classical circuit model to clarify the role of quantum entanglement in the recently discovered encoding phase transitions in quantum circuits with measurements. As a starting point we define a random circuit model with…

Quantum Physics · Physics 2023-05-12 Anasuya Lyons , Soonwon Choi , Ehud Altman

Repeated measurements can induce entanglement phase transitions in the dynamics of quantum systems. Interacting models, both chaotic and integrable, generically show a stable volume-law entangled phase at low measurement rates which…

Quantum Physics · Physics 2024-05-21 Luca Lumia , Emanuele Tirrito , Rosario Fazio , Mario Collura

Dual-unitary circuits have emerged as a minimal model for chaotic quantum many-body dynamics in which the dynamics of correlations and entanglement remains tractable. Simultaneously, there has been intense interest in the effect of…

Quantum Physics · Physics 2023-02-09 Pieter W. Claeys , Marius Henry , Jamie Vicary , Austen Lamacraft

Scrambling unitary dynamics in a quantum system transmutes local quantum information into a non-local web of correlations which manifests itself in a complex spatio-temporal pattern of entanglement. In such a context, we show there can…

Quantum Physics · Physics 2025-06-02 Alan Sherry , Sthitadhi Roy

We develop a dynamical framework for quantum measurement based on stochastic but unitary evolution in projective state space. Random Hamiltonians drawn from the Gaussian Unitary Ensemble generate stochastic unitary dynamics of the quantum…

Quantum Physics · Physics 2026-01-27 Alexey A. Kryukov

This paper is dedicated to a detailed analysis and computation of quantum states of causal fermion systems. The mathematical core is to compute integrals over the unitary group asymptotically for a large dimension of the group, for various…

Mathematical Physics · Physics 2024-07-17 Felix Finster , Niky Kamran , Moritz Reintjes