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We investigate quantum dynamical systems defined on a finite dimensional Hilbert space and subjected to an interaction with an environment. The rate of decoherence of initially pure states, measured by the increase of their von Neumann…

Quantum Physics · Physics 2009-11-10 Robert Alicki , Artur Lozinski , Prot Pakonski , Karol Zyczkowski

We compute analytically the statistics of the Renyi and von Neumann entropies (standard measures of entanglement), for a random pure state in a large bipartite quantum system. The full probability distribution is computed by first mapping…

Statistical Mechanics · Physics 2011-05-30 Celine Nadal , Satya N Majumdar , Massimo Vergassola

In quantum physics, measurements give random results and yield a corresponding random back action on the state of the system subject to measurement. If a quantum system is probed continuously over time, its state evolves along a stochastic…

Quantum Physics · Physics 2016-03-28 N. Foroozani , M. Naghiloo , D. Tan , K. Mølmer , K. W. Murch

Von Neumann measurement framework describes a dynamic interaction between a target system and a probe. In contrast, a quantum controlled measurement framework uses a qubit probe to control the actions of different operators on the target…

Quantum Physics · Physics 2020-06-03 Le Bin Ho

In the standard von Neumann interaction used in Quantum measurements, the chosen observable to which the environment (apparatus) entangles is exactly reproduced in the state of the environment, thereby decohering the quantum system in the…

Quantum Physics · Physics 2024-01-11 Adarsh S , P. N. Bala Subramanian , T. P. Sreeraj

One of the main postulates of quantum mechanics is that measurements destroy quantum coherence (wave function collapse). Recently it was discovered that in a many-body system dilute local measurements still preserve some coherence across…

Quantum Physics · Physics 2025-05-13 Aleksei Khindanov , Igor L. Aleiner , Lara Faoro , Lev B. Ioffe

In general, the state of a quantum system represented by density operator and its determination is a fundamental problem in quantum mechanics. A method of direct measurement of matrix element of density operator of a single two dimensional…

Quantum Physics · Physics 2022-02-16 Yusuf Turek

In this letter, we have considered an electron in a double quantum dot system interacting with a detector represented by a point contact. We present a dynamical model for the gradual decoherence of the density matrix due to the interaction…

Mesoscale and Nanoscale Physics · Physics 2017-11-29 H. Cruz

Quantum coherence is the most distinguished signature of quantum mechanics, also recognized to be an essential resource for many promising quantum technologies, playing a central role in phenomena related to quantum information science,…

Quantum Physics · Physics 2019-02-27 Bertúlio de Lima Bernardo

We consider a controlled quantum system whose finite dimensional state is governed by a discrete-time nonlinear Markov process. In open-loop, the measurements are assumed to be quantum non-demolition (QND). The eigenstates of the measured…

Optimization and Control · Mathematics 2015-03-19 Hadis Amini , Abhinav Somaraju , Igor Dotsenko , Clement Sayrin , Mazyar Mirrahimi , Pierre Rouchon

The entangled "measurement state" (MS), predicted by von Neumann to arise during quantum measurement, seems to display paradoxical properties such as multiple macroscopic outcomes. But analysis of interferometry experiments using entangled…

Quantum Physics · Physics 2022-02-01 Art Hobson

For a class of interacting particle systems in continuous space, we show that finite-volume approximations of the bulk diffusion matrix converge at an algebraic rate. The models we consider are reversible with respect to the Poisson…

Probability · Mathematics 2021-12-07 Arianna Giunti , Chenlin Gu , Jean-Christophe Mourrat

Quantum measurements can produce randomness arising from the uncertainty principle. When measuring a state with von Neumann measurements, the intrinsic randomness can be quantified by the quantum coherence of the state on the measurement…

Quantum Physics · Physics 2022-03-17 Hao Dai , Boyang Chen , Xingjian Zhang , Xiongfeng Ma

We present a quantum algorithm based on repeated measurement to solve initial-value problems for nonlinear ordinary differential equations (ODEs), which may be generated from partial differential equations in plasma physics. We map a…

Quantum Physics · Physics 2025-04-30 Joseph Andress , Alexander Engel , Yuan Shi , Scott Parker

We consider the continuous measurement of a double quantum dot by a weakly coupled detector (tunnel point contact nearby). While the conventional approach describes the gradual system decoherence due to the measurement, we study the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Alexander N. Korotkov

We derive the theory of open quantum system dynamics intervened by a series of nonselective measurements. We analyze the cases of time independent and time dependent Hamiltonian dynamics in between the measurements and find the approximate…

Quantum Physics · Physics 2018-01-17 Sergey N. Filippov

We investigate the power of weak measurements in the framework of quantum state discrimination. First, we define and analyze the notion of weak consecutive measurements. Our main result is a convergence theorem whereby we demonstrate when…

Quantum Physics · Physics 2015-06-23 Boaz Tamir , Eliahu Cohen , Avner Priel

Randomly repeated measurements during the evolution of a closed quantum system create a sequence of probabilities for the first detection of a certain quantum state. The related discrete monitored evolution for the return of the quantum…

Quantum Physics · Physics 2021-09-30 K. Ziegler , E. Barkai , D. Kessler

This paper considers the Linear Minimum Variance recursive state estimation for the linear discrete time dynamic system with random state transition and measurement matrices, i.e., random parameter matrices Kalman filtering. It is shown…

Information Theory · Computer Science 2007-07-13 Dandan Luo , Yunmin Zhu

Consider the question: what statistical ensemble corresponds to minimal prior knowledge about a quantum system ? For the case where the system is in fact known to be in a pure state there is an obvious answer, corresponding to the unique…

Quantum Physics · Physics 2009-10-31 Michael J. W. Hall