Unsharp observables and CHSH inequalities

1995 ◽  
Vol 199 (1-2) ◽  
pp. 12-14 ◽  
Author(s):  
G. Kar ◽  
S. Roy
2013 ◽  
Vol 6 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Ehtibar N. Dzhafarov ◽  
Janne V. Kujala
Keyword(s):  

2017 ◽  
Vol 50 (25) ◽  
pp. 255301 ◽  
Author(s):  
M O Renou ◽  
D Rosset ◽  
A Martin ◽  
N Gisin
Keyword(s):  

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 163
Author(s):  
Karl Hess

This review is related to the Einstein-Bohr debate and to Einstein–Podolsky–Rosen’s (EPR) and Bohm’s (EPRB) Gedanken-experiments as well as their realization in actual experiments. I examine a significant number of papers, from my minority point of view and conclude that the well-known theorems of Bell and Clauser, Horne, Shimony and Holt (CHSH) deal with mathematical abstractions that have only a tenuous relation to quantum theory and the actual EPRB experiments. It is also shown that, therefore, Bell-CHSH cannot be used to assess the nature of quantum entanglement, nor can physical features of entanglement be used to prove Bell-CHSH. Their proofs are, among other factors, based on a statistical sampling argument that is invalid for general physical entities and processes and only applicable for finite “populations”; not for elements of physical reality that are linked, for example, to a time-like continuum. Bell-CHSH have, furthermore, neglected the subtleties of the theorem of Vorob’ev that includes their theorems as special cases. Vorob’ev found that certain combinatorial-topological cyclicities of classical random variables form a necessary and sufficient condition for the constraints that are now known as Bell-CHSH inequalities. These constraints, however, must not be linked to the observables of quantum theory nor to the actual EPRB experiments for a variety of reasons, including the existence of continuum-related variables and appropriate considerations of symmetry.


2010 ◽  
Vol 81 (6) ◽  
Author(s):  
Sixia Yu ◽  
Nai-le Liu ◽  
Li Li ◽  
C. H. Oh

1997 ◽  
Vol 27 (10) ◽  
pp. 1323-1343 ◽  
Author(s):  
Gianpiero Cattaneo ◽  
Tiziana Marsico ◽  
Giuseppe Nisticò ◽  
Guido Bacciagaluppi

2006 ◽  
Vol 13 (03) ◽  
pp. 281-289
Author(s):  
F. A. Bovino ◽  
G. Castagnoli ◽  
A. Ekert ◽  
C. Moura Alves ◽  
P. Horodecki ◽  
...  

Nonlinear properties of quantum states, such as entropy or entanglement, quantify important physical resources and are frequently used in quantum information science. They are usually calculated from a full description of a quantum state, even though they depend only on a small number of parameters that specify the state. Here we extract a nonlocal and a nonlinear quantity, namely the Renyi entropy, from local measurements on two pairs of polarization entangled photons. We also introduce a "phase marking" technique which allows to select uncorrupted outcomes even with nondeterministic sources of entangled photons. We use our experimental data to demonstrate the violation of entropic inequalities. They are examples of a nonlinear entanglement witness and their power exceeds all linear tests for quantum entanglement based on all possible Bell-CHSH inequalities.


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