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It is proposed a possible new approach of quantum measurements (QMS), disconnected of the traditional interpretation of uncertainty relations and independent of any appeal to the strange idea of collapse (reduction) of wave functions. The…

Quantum Physics · Physics 2007-05-23 S. Dumitru

Quantum entanglement is usually revealed via a well aligned, carefully chosen set of measurements. Yet, under a number of experimental conditions, for example in communication within multiparty quantum networks, noise along the channels or…

One of the basic lessons of quantum theory is that one cannot obtain information on an unknown quantum state without disturbing it. Hence, by performing a certain measurement, we limit the other possible measurements that can be effectively…

Quantum Physics · Physics 2018-08-24 Erkka Haapasalo , Teiko Heinosaari , Takayuki Miyadera

When working to understand quantum systems engineering, there are many constraints to building a scalable quantum computer. Here I discuss a constraint on the qubit control system from an information point of view, showing that the large…

Quantum Physics · Physics 2020-12-29 John M. Martinis

The problem of measurement in quantum mechanics is reanalyzed within a general, strictly probabilistic framework (without reduction postulate). Based on a novel comprehensive definition of measurement the natural emergence of objective…

Quantum Physics · Physics 2007-05-23 Markus Simonius

Quantum-enhanced measurements use quantum mechanical effects in order to enhance the sensitivity of the measurement of classical quantities, such as the length of an optical cavity. The major goal is to beat the standard quantum limit…

Quantum Physics · Physics 2011-03-10 Daniel Braun , John Martin

We study quantum measurement with preselection and postselection, and derive the precise expressions of the measurement results without any restriction on the coupling strength between the system and the measuring device. For a qubit…

Quantum Physics · Physics 2011-11-18 Xuanmin Zhu , Yuxiang Zhang , Shengshi Pang , Chang Qiao , Quanhui Liu , Shengjun Wu

All information in quantum systems is, notwithstanding Bell's theorem, localised. Measuring or otherwise interacting with a quantum system S has no effect on distant systems from which S is dynamically isolated, even if they are entangled…

Quantum Physics · Physics 2007-05-23 David Deutsch , Patrick Hayden

A model of quantum measurement, illustrated using the spin--boson model, is formulated in terms of a cascading pair of quantum phase transitions. The first produces the desired superposition of macroscopic responses to the microscopic state…

Statistical Mechanics · Physics 2019-12-19 Peter B. Weichman

Two categories of results regarding quantum measurements are derived in this work and applied to the problem of collapse. The first category is concerned with local and transient features of the entanglement between a macroscopic measuring…

Quantum Physics · Physics 2016-03-01 Roland Omnès

We propose a formulation of quantum measurement within a modified framework of frames, in which a quantum system - a single qubit - is directly coupled to a classical measurement bit. The qubit is represented as a positive probability…

Quantum Physics · Physics 2025-12-04 Dagomir Kaszlikowski , Pawel Kurzynski

Quantum superposition, collapse of wave function and quantum measurement problem are reexamined based on nonadiabatic dressed states and experimental observations on the quantum transitions. The physical mechanisms behind these processes…

Quantum Physics · Physics 2023-12-25 I. G. Koprinkov

This paper explores the problem of quantum measurement complexity. In computability theory, the complexity of a problem is determined by how long it takes an effective algorithm to solve it. This complexity may be compared to the difficulty…

Quantum Physics · Physics 2014-10-27 Subhash Kak

The so-called quantum measurement problems are solved from a new perspective. One of the main observations is that the basic entities of our world are {\it particles}, elementary or composite. It follows that each elementary process, hence…

Quantum Physics · Physics 2023-02-20 Kenichi Konishi

In the present study we revisit the application of the $q$-information measures $R_q$ of R\'enyi's and $S_q$ of Tsallis' to the discussion of special features of two qubits systems. More specifically, we study the correlations between the…

Quantum Physics · Physics 2015-06-26 J. Batle , M. Casas , A. Plastino , A. R. Plastino

During a continuous measurement, quantum systems can be described by a stochastic Schr\"odinger equation which, in the appropriate limit, reproduces the von Neumann wave-function collapse. The average behavior on the ensemble of all…

Condensed Matter · Physics 2009-10-30 Carlo Presilla , Ubaldo Tanbini

A recurring problem in quantum mechanics is to estimate either the state of a quantum system or the measurement operator applied to it. If we wish to estimate both, then the difficulty is that the state and the measurement always appear…

Quantum Physics · Physics 2020-06-12 I. D. Moore , S. J. van Enk

We found that in contrast with the common premise, a measurement on the environment of an open quantum system can {\em reduce} its decoherence rate. We demonstrate it by studying an example of indirect qubit's measurement, where the…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Yin Ye , Yunshan Cao , Xin-Qi Li , Shmuel Gurvitz

We show that given a quantum measurement, for an overwhelming majority of pure states, no meaningful information is produced. This is independent of the number of outcomes of the quantum measurement. Due to conservation inequalities, such…

Computational Complexity · Computer Science 2021-05-17 Samuel Epstein

Measurement is one of the key concepts which discriminates classical and quantum physics. Unlike classical systems, a measurement on a quantum system typically alters it drastically as a result of wave function collapse. Here we suggest…

Quantum Physics · Physics 2018-07-18 Abolfazl Bayat , Bedoor Alkurtass , Pasquale Sodano , Henrik Johannesson , Sougato Bose