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We present a simple experimental scheme which can be used to demonstrate an all-or-nothing type contradiction between non-contextual hidden variables and quantum mechanics. The scheme, which is inspired by recent ideas by Cabello and…

Quantum Physics · Physics 2009-11-06 Christoph Simon , Marek Zukowski , Harald Weinfurter , Anton Zeilinger

The question about the existence of so-called ``hidden'' variables in quantum mechanics and the perception of the completeness of quantum mechanics are two sides of the same coin. Quantum analytical mechanics constitutes a completion of…

Quantum Physics · Physics 2026-05-01 Wolfgang Paul

It is shown that quantum mechanics is noncontextual if quantum properties are represented by subspaces of the quantum Hilbert space (as proposed by von Neumann) rather than by hidden variables. In particular, a measurement using an…

Quantum Physics · Physics 2013-02-21 Robert B. Griffiths

Recent experiments and theory have further illuminated the concept of "quantum contextuality". In this paper we take an inequality - the Pentagram (or KCBS) inequality, which is violated by an unentangled spin-1 system - and given a relaxed…

Quantum Physics · Physics 2015-06-16 William N. Plick , Radek Lapkiewicz

The contextuality of quantum mechanics, i.e. the measurement outcome dependence upon previously made measurements, can be shown by the violation of inequalities based on measurements of well chosen observables. An important property of such…

Quantum Physics · Physics 2017-03-16 A. Laversanne-Finot , A. Ketterer , M. R. Barros , S. P. Walborn , T. Coudreau , A. Keller , P. Milman

We discuss two questions related to the concept of weak values as seen from the standard quantum-mechanics point of view. In the first part of the paper, we describe a scenario where unphysical results similar to those encountered in the…

Quantum Physics · Physics 2009-07-29 S. Ashhab , Franco Nori

The spin-statistics connection is derived in a simple manner under the postulates that the original and the exchange wave functions are simply added, and that the azimuthal phase angle, which defines the orientation of the spin part of each…

Quantum Physics · Physics 2014-02-04 Arthur Jabs

In this manuscript, we consider a scenario in which a spin-1/2 quanton goes through a superposition of co-rotating and counter-rotating geodetic circular paths, which play the role of the paths of a Mach-Zehnder interferometer in a…

General Relativity and Quantum Cosmology · Physics 2021-07-23 Marcos L. W. Basso , Jonas Maziero

Spin is commonly thought to reflect the true quantum nature of microphysics. We show that spin is related to intrinsic and field-like properties of single particles. These properties change continuously in external magnetic fields.…

Quantum Physics · Physics 2007-05-23 W. A. Hofer

We analyze in mathematical detail, within the framework of the QMUPL model of spontaneous wave function collapse, the von Neumann measurement scheme for the measurement of a 1/2 spin particle. We prove that, according to the equation of the…

Quantum Physics · Physics 2009-11-13 A. Bassi , D. G. M. Salvetti

Observations or measurements taken of a quantum system (a small number of fundamental particles) are inherently random. If the state of the system depends on unknown parameters, then the distribution of the outcome depends on these…

Statistics Theory · Mathematics 2007-06-13 Richard D. Gill

It is a well-known fact that all the statistical predictions of quantum mechanics on the state of any physical system represented by a two-dimensional Hilbert space can always be duplicated by a noncontextual hidden-variables model. In this…

Quantum Physics · Physics 2009-10-30 Adan Cabello

We propose a critical dissipaive quantum metrology schemes for single parameter estimation which are based on a quantum probe consisting of coherently driven ensemble of $N$ spin-1/2 particles under the effect of squeezed, collective spin…

Quantum Physics · Physics 2023-08-16 Venelin P. Pavlov , Diego Porras , Peter A. Ivanov

The quantum dynamics of a spin-1/2 charged particle in the presence of magnetic field is analyzed for the general case where scalar and vector couplings are considered. The energy spectra are explicitly computed for different physical…

High Energy Physics - Theory · Physics 2015-07-13 Luis B. Castro , Edilberto O. Silva

Proofs of Bell-Kochen-Specker contextuality demonstrate that there exists sets of projectors that cannot each be assigned either 0 or 1 such that each basis formed from them contains exactly one 1-assigned projector. Instead, at least some…

Quantum Physics · Physics 2017-12-12 Andrew W. Simmons

Models of a phenomenon are often developed by examining it under different experimental conditions, or measurement contexts. The resultant probabilistic models assume that the underlying random variables, which define a measurable set of…

Artificial Intelligence · Computer Science 2018-02-05 Peter D. Bruza

A quantum spin-$\frac{1}{2}$ chain with an axial symmetry is normally described by quasiparticles associated with the spins oriented along the axis of rotation. Kinetic constraints can enrich such a description by setting apart different…

Quantum Physics · Physics 2024-04-25 Maurizio Fagotti

A class of signed joint probability measures for n arbitrary quantum observables is derived and studied based on quasi-characteristic functions with symmetrized operator orderings of Margenau-Hill type. It is shown that the Wigner…

Quantum Physics · Physics 2024-10-01 Ralph Sabbagh , Olga Movilla Miangolarra , Hamid Hezari , Tryphon T. Georgiou

The contextuality and noncontextuality notions are considered in framework of probability representation of quantum states. Example of qutrit states and violation of the noncontextuality inequalities are presented by using the spin tomogram…

Quantum Physics · Physics 2013-04-30 A. A. Strakhov , V. I. Man'ko

Physical potentials are routinely approximated to harmonic potentials so as to analytically solve the system dynamics. Often it is important to know when a quantum harmonic oscillator (QHO) behaves quantum mechanically and when classically.…

Quantum Physics · Physics 2016-03-23 Hemant Katiyar , C. S. Sudheer Kumar , T. S. Mahesh