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A new approach to quantum walks is presented. Considering a quantum system undergoing some unitary discrete-time evolution in a directed graph G, we think of the vertices of G as sites that are occupied by the quantum system, whose internal…

Quantum Physics · Physics 2015-06-09 Chaobin Liu

Rapid-purification by feedback --- specifically, reducing the mean impurity faster than by measurement alone --- can be achieved by making the eigenbasis of the density matrix to be unbiased relative to the measurement basis. Here we…

Quantum Physics · Physics 2010-11-30 Joshua Combes , Howard M. Wiseman , Kurt Jacobs , Anthony J. O'Connor

The intensely studied measurement-induced entanglement phase transition has become a hallmark of non-unitary quantum many-body dynamics. Usually, such a transition only shows up at the level of each individual quantum trajectory, and is…

Statistical Mechanics · Physics 2023-07-26 Vikram Ravindranath , Yiqiu Han , Zhi-Cheng Yang , Xiao Chen

The experimental detection of non-equilibrium quantum criticality remains a challenge, as traditional signatures like dynamical quantum phase transitions rely on hard-to-measure global properties. Here, we demonstrate that local connected…

Quantum Gases · Physics 2026-05-19 Xiaofeng Wu , Xin Wang , Sixun Jia , Bo Xiong

We summarize recent work showing that the $1/r^2$ model of interacting particles in 1-dimension is a universal Hamiltonian for quantum chaotic systems. The problem is analyzed in terms of random matrices and of the evolution of their…

Condensed Matter · Physics 2025-07-04 B. Sriram Shastry

We investigate the role of a statistical complexity measure to assign equilibration in isolated quantum systems. While unitary dynamics preserve global purity, expectation values of observables often exhibit equilibration-like behavior,…

Quantum Physics · Physics 2025-08-14 Marcos G. Alpino , Tiago Debarba , Reinaldo O. Vianna , André T. Cesário

This paper aims at presenting a few models of quantum dynamics whose description involves the analysis of random unitary matrices for which dynamical localization has been proven to hold. Some models come from physical approximations…

Mathematical Physics · Physics 2011-05-03 Alain Joye

Quantum circuits offer a versatile platform for simulating digital quantum dynamics and uncovering novel states of non-equilibrium quantum matter. One principal example are measurement-induced phase transitions arising from non-unitary…

Quantum Physics · Physics 2025-06-10 Kai Klocke , Daniel Simm , Guo-Yi Zhu , Simon Trebst , Michael Buchhold

In this paper we approach the theory of continuous measurements and the associated unconditional and conditional (stochastic) master equations from the perspective of quantum information and quantum computing. We do so by showing how the…

Quantum Physics · Physics 2022-03-15 Jonathan A. Gross , Carlton M. Caves , Gerard J. Milburn , Joshua Combes

We develop a general framework to study quantum trajectories resulting from repeated random measurements subject to stationary noise, and generalize results of K\"ummerer and Maassen to this setting. The resulting trajectory of quantum…

Quantum Physics · Physics 2025-11-13 Owen Ekblad , Eloy Moreno-Nadales , Lubashan Pathirana , Jeffrey Schenker

The implementation and practicality of quantum algorithms highly hinge on the quality of operations within a quantum processor. Therefore, including realistic error models in quantum computing simulation platforms is crucial for testing…

Quantum Physics · Physics 2021-04-12 Ahmed Abid Moueddene , Nader Khammassi , Koen Bertels , Carmen G. Almudever

We establish an operational connection between discrete rounds of generalized measurements and continuous-time decoherence, with an explicit correspondence between the number of measurement rounds and the evolution time. Operationally, we…

Quantum Physics · Physics 2026-03-12 Zhenyu Xu

Classical simulation of quantum systems plays an important role in the study of many-body phenomena and in the benchmarking and verification of quantum technologies. Exact simulation is often limited to small systems because the dimension…

Quantum Physics · Physics 2024-06-04 Dominik S. Wild , Sabina Drăgoi , Corbin McElhanney , Jonathan Wurtz , Sheng-Tao Wang

In finite dimension, the long-time and metastable behavior of a gradient flow perturbated by a small Brownian noise is well understood. A similar situation arises when a Wasserstein gradient flow over a space of probability measure is…

Probability · Mathematics 2025-10-21 Pierre Monmarché

Characterizing and quantifying quantum correlations in states of many-particle systems is at the core of a full understanding of phase transitions in matter. In this work, we continue our investigation of the notion of generalized…

Quantum Physics · Physics 2009-11-10 Rolando Somma , Gerardo Ortiz , Howard Barnum , Emanuel Knill , Lorenza Viola

Quantum computing gives direct access to the study of real-time dynamics of quantum many-body systems. In principle, it is possible to directly calculate non-equal-time correlation functions, from which one can detect interesting phenomena,…

In this manuscript we address the problem of deriving \emph{analytic} expressions for calculating universal decoherence-induced errors in qubits undergoing arbitrary, unitary, time-dependent quantum-control protocols. For a qubit undergoing…

Quantum Physics · Physics 2015-06-12 Todd J. Green , Jarrah Sastrawan , Hermann Uys , Michael J. Biercuk

We develop analytical tools and numerical methods for time evolving the total density matrix of the finite-size Anderson model. The model is composed of two finite metal grains, each prepared in canonical states of differing chemical…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Manas Kulkarni , Kunal L Tiwari , Dvira Segal

Assuming Markovian time evolution of a quantum sensing system, we study the general characterization of the optimal sensitivity scalings with time, under most general quantum control protocols. We allow the estimated parameter to influence…

Quantum Physics · Physics 2025-02-12 Arpan Das , Wojciech Gorecki , Rafal Demkowicz-Dobrzanski

The dynamics of quantum systems far from equilibrium represents one of the most challenging problems in theoretical many-body physics. While the evolution is in general intractable in all its details, relevant observables can become…