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Related papers: Anomalous Weak Values Are Proofs of Contextuality

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We examine weak measurements of arbitrary observables where the object is prepared in a mixed state and on which measurements with imperfect detectors are made. The weak value of an observable can be expressed as a conditional expectation…

Quantum Physics · Physics 2009-11-10 Lars M. Johansen , Alfredo Luis

Measurements in classical and quantum physics are described in fundamentally different ways. Nevertheless, one can formally define similar measurement procedures with respect to the disturbance they cause. Obviously, strong measurements,…

Quantum Physics · Physics 2013-03-05 Adam Bednorz , Kurt Franke , Wolfgang Belzig

A quantum transition can be seen as a result of interference between various pathways(e.g. Feynman paths) which can be labelled by a variable $f$. An attempt to determine the value of f without destroying the coherence between the pathways…

Quantum Physics · Physics 2009-05-26 D. Sokolovski

Contextuality and entanglement are valuable resources for quantum computing and quantum information. Bell inequalities are used to certify entanglement; thus, it is important to understand why and how they are violated. Quantum mechanics…

Quantum Physics · Physics 2021-08-30 Marian Kupczynski

We extend the idea of weak measurements to the general case, provide a complete treatment and obtain results for both the regime when the pre-selected and post-selected states (PPS) are almost orthogonal and the regime when they are exactly…

Quantum Physics · Physics 2015-03-17 Shengjun Wu , Yang Li

Some recent attempts at measuring non local weak values via local measurements are discussed and shown to be less robust than standard weak measurements. A method for measuring some non local weak values via non local measurements (non…

Quantum Physics · Physics 2011-07-12 Aharon Brodutch , Lev Vaidman

We investigate in this work the meaning of weak values through the prism of property ascription in quantum systems. Indeed, the weak measurements framework contains only ingredients of the standard quantum formalism, and as such weak…

Quantum Physics · Physics 2019-03-25 A. Matzkin

Quantum weak measurement, measuring some observable quantities within the selected subensemble of the entire quantum ensemble, can produce many interesting results such as the superluminal phenomena. An outcome of such a measurement is the…

Quantum Physics · Physics 2017-01-24 Miao Zhang

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

Contextuality is one way of capturing the non-classicality of quantum theory. The contextual nature of a theory is often witnessed via the violation of non-contextuality inequalities---certain linear inequalities involving probabilities of…

Quantum Physics · Physics 2020-07-08 Kishor Bharti , Atul Singh Arora , Leong Chuan Kwek , Jérémie Roland

Weak measurements with imaginary weak values are reexamined in light of recent experimental results. The shift of the meter, due to the imaginary part of the weak value, is derived via the probability of postselection, which allows…

Quantum Physics · Physics 2014-07-16 Yaron Kedem

Weak values are average quantities,therefore investigating their associated variance is crucial in understanding their place in quantum mechanics. We develop the concept of a position-postselected weak variance of momentum as cohesively as…

Quantum Physics · Physics 2015-08-10 M. R. Feyereisen

The notion of weak measurement provides a formalism for extracting information from a quantum system in the limit of vanishing disturbance to its state. Here we extend this formalism to the measurement of sequences of observables. When…

Quantum Physics · Physics 2009-11-13 Graeme Mitchison , Richard Jozsa , Sandu Popescu

The Contextuality-by-Default approach to determining and measuring the (non)contextuality of a system of random variables requires that every random variable in the system be represented by an equivalent set of dichotomous random variables.…

Quantum Physics · Physics 2022-01-05 Janne V. Kujala , Ehtibar N. Dzhafarov

It is demonstrated that a weak measurement of the squared quadrature observable may yield negative values for coherent states. This result cannot be reproduced by a classical theory where quadratures are stochastic $c$-numbers. The real…

Quantum Physics · Physics 2009-11-10 Lars M. Johansen

A new measure of non-classical correlations is introduced and characterized. It tests the ability of using a state {\rho} of a composite system AB as a probe for a quantum illumination task [e.g. see S. Lloyd, Science 321, 1463 (2008)], in…

Quantum Physics · Physics 2014-07-17 A. Farace , A. De Pasquale , L. Rigovacca , V. Giovannetti

In quantum physics the term `contextual' can be used in more than one way. One usage, here called `Bell contextual' since the idea goes back to Bell, is that if $A$, $B$ and $C$ are three quantum observables, with $A$ compatible (i.e.,…

Quantum Physics · Physics 2019-09-19 Robert B. Griffiths

Contextuality is a non-classical behaviour that can be exhibited by quantum systems. It is increasingly studied for its relationship to quantum-over-classical advantages in informatic tasks. To date, it has largely been studied in…

Quantum Physics · Physics 2022-04-20 Rui Soares Barbosa , Tom Douce , Pierre-Emmanuel Emeriau , Elham Kashefi , Shane Mansfield

Contextuality - the obstruction to describing quantum mechanics in a classical statistical way - has been proposed as a resource that powers quantum computing. The measurement-based model provides a concrete manifestation of contextuality…

Quantum Physics · Physics 2018-10-12 Markus Frembs , Sam Roberts , Stephen D. Bartlett

Quantum nonlocality offers a secure way to produce random numbers: their unpredictability is intrinsic and can be certified just by observing the statistic of the measurement outcomes, without assumptions on how they are produced. To do…

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