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The interplay between unitary dynamics and quantum measurements induces diverse phenomena in open quantum systems with no counterparts in closed quantum systems at equilibrium. Here, we generally classify Kraus operators and their effective…

Statistical Mechanics · Physics 2025-11-12 Zhenyu Xiao , Kohei Kawabata

The dynamics of entanglement in `hybrid' non-unitary circuits (for example, involving both unitary gates and quantum measurements) has recently become an object of intense study. A major hurdle toward experimentally realizing this physics…

Disordered Systems and Neural Networks · Physics 2021-02-11 Matteo Ippoliti , Vedika Khemani

Monitored quantum systems, where unitary dynamics compete with continuous measurements, exhibit dynamical transitions as the measurement rate is varied. These reflect abrupt changes in the structure of the evolving wavefunction, captured by…

We study quantum circuits consisting of unitary gates, projective measurements, and control operations that steer the system towards a pure absorbing state. Two types of phase transition occur as the rate of these control operations is…

Quantum Physics · Physics 2023-06-07 Lorenzo Piroli , Yaodong Li , Romain Vasseur , Adam Nahum

Unitary circuits subject to repeated projective measurements can undergo an entanglement phase transition (EPT) as a function of the measurement rate. This transition is generally understood in terms of a competition between the scrambling…

A wave function exposed to measurements undergoes pure state dynamics, with deterministic unitary and probabilistic measurement induced state updates, defining a quantum trajectory. For many-particle systems, the competition of these…

Statistical Mechanics · Physics 2021-11-02 M. Buchhold , Y. Minoguchi , A. Altland , S. Diehl

Adaptive quantum circuits, in which unitary operations, measurements, and feedback are used to steer quantum many-body systems, provide an exciting opportunity to generate new dynamical steady states. We introduce an adaptive quantum…

Quantum Physics · Physics 2023-04-27 Jacob Hauser , Yaodong Li , Sagar Vijay , Matthew P. A. Fisher

We study the entanglement behavior of a random unitary circuit punctuated by projective measurements at the measurement-driven phase transition in one spatial dimension. We numerically study the logarithmic entanglement negativity of two…

Statistical Mechanics · Physics 2021-08-31 Bowen Shi , Xin Dai , Yuan-Ming Lu

We investigate quantum phase transitions in which a change in the type of entanglement from bound entanglement to either free entanglement or separability may occur. In particular, we present a theoretical method to construct a class of…

Quantum Physics · Physics 2010-04-08 S. Baghbanzadeh , S. Alipour , A. T. Rezakhani

We investigate the interplay between unitary and non-unitary driven many-body dynamics in (1+1)-dimensional quantum critical systems described by conformal field theory (CFT). By formulating a coherent state approach, we demonstrate that…

Strongly Correlated Electrons · Physics 2025-09-29 Bastien Lapierre , Pietro Pelliconi , Shinsei Ryu , Julian Sonner

Quantum entanglement in systems of identical particles is often obscured by the interplay between exchange-induced correlations and the operational framework used to define entanglement. To study the role of exchange statistics, we propose…

Quantum Physics · Physics 2026-04-22 M. F. V. Oliveira , F. A. B. F. de Moura , M. L. Lyra , G. M. A. Almeida

A basic diagnostic of entanglement in mixed quantum states is known as the positive partial transpose (PT) criterion. Such criterion is based on the observation that the spectrum of the partially transposed density matrix of an entangled…

Statistical Mechanics · Physics 2019-09-25 Hassan Shapourian , Paola Ruggiero , Shinsei Ryu , Pasquale Calabrese

Monitored quantum circuits can exhibit an entanglement transition as a function of the rate of measurements, stemming from the competition between scrambling unitary dynamics and disentangling projective measurements. We study how…

Disordered Systems and Neural Networks · Physics 2022-10-11 Utkarsh Agrawal , Aidan Zabalo , Kun Chen , Justin H. Wilson , Andrew C. Potter , J. H. Pixley , Sarang Gopalakrishnan , Romain Vasseur

We explore the Lyapunov spectrum and entanglement entropy in systems evolved by quantum measurements and spatially homogeneous unitary gates. In models with temporally random and Floquet unitary gates, we find that the Lyapunov exponents…

Quantum Physics · Physics 2025-07-16 Ken Mochizuki , Ryusuke Hamazaki

Quantum phase transitions also occur in non-Hermitian systems. In this work we show that density functional theory, for the first time, uncovers universal behaviors for phase transitions in non-Hermitian many-body systems. To be specific,…

Quantum Physics · Physics 2017-08-10 Bo-Bo Wei , Liang Jin

The description of the entanglement dynamics of monitored noninteracting fermions, including the existence of measurement-induced phase transitions (MIPTs), is a challenging problem with conflicting results in the literature. The mapping of…

Quantum Physics · Physics 2026-04-06 Bo Fan , Can Yin , Antonio M. García-García

It is shown that discrete-time quantum walks can be used to digitize, i.e., to time discretize fermionic models of continuous-time lattice gauge theory. The resulting discrete-time dynamics is thus not only manifestly unitary, but also…

Quantum Physics · Physics 2025-02-28 Pablo Arnault , Armando Pérez , Pablo Arrighi , Terry Farrelly

We study the dynamics under continuous measurements for free fermions in a quasiperiodic potential by using the Aubry-Andr\'{e}-Harper model with hopping rate $J$ and potential strength $V$. On the basis of the quantum trajectory method, we…

Quantum Gases · Physics 2025-08-20 Toranosuke Matsubara , Kazuki Yamamoto , Akihisa Koga

We present a quantum circuit model which emulates the interface growth of the classical raise-and-peel model. Our model consists of Clifford unitary gates interspersed with projective measurements, applied according to prescribed feedback…

Quantum Physics · Physics 2024-08-08 Eliot Heinrich , Xiao Chen

We analyse the discrete-time dynamics of a model of non-interacting fermions coupled to an infinite reservoir formed by a bosonic quantum walk on ${\mathbb Z}$. This dynamics consists of consecutive applications of free evolutions of the…

Mathematical Physics · Physics 2025-07-21 Olivier Bourget , Alain Joye , Dominique Spehner