We emphasize the difficulties of an experiment that can definitely discriminate between local realistic hidden variables theories and quantum mechanics using the Bell CHSH inequalities and a real measurement apparatus. In particular we analyze some examples in which the noise in real instruments can alter the experimental results, and the nontrivial problem to find a real “fair sample” of parti...

– Bell’s inequalities are a variant of Boole’s legendary consistency “conditions of possible experience.” Although they do not specifically refer to spatially separated subsystems, they apply to spatially separated particles as well. Such an interpretation appears to be immune to arguments involving time dependencies put forward recently by Hess and Philipp [1]. In the middle of the 19th centur...

We consider tripartite entangled states for continuous variable systems of EPR type, which generalise the famous bipartite CV EPR states (eigenvectors of conjugate choices X1−X2, P1+ P2, of the systems’ total and relative position and momentum variables, respectively). We give the regularised forms of such tripartite EPR states in second-quantised formulation, and derive their Wigner functions....

Today we are going to talk about an infinite hierarchy of semidefinite programmings which attempts to approximate the entangled value of multi-prover games [1]. This work is based on a recent result called non-commutative Positivstellensatz [2] about the representation of positive polynomials. In a one-round two-prover cooperative game, a verifier asks questions to two provers, Alice and Bob, w...

Kar’s recent proof showing that a maximally entangled state of two spin-1/2 particles gives the largest violation of a Bell inequality is extended to N spin-1/2 particles (N ≥ 3). In particular, it is shown that all the states yielding a direct contradiction with the assumption of local realism do generally consist of a superposition of maximally entangled states. Recently, Kar (see Ref. [1], a...

We investigate the scenario where an observer, Alice, shares a two-qubit state with arbitrary number of observers, Bobs, via sequentially and independently recycling qubit in possession first Bob. It is known that there exist entangled states which can be used to have arbitrarily long sequence Bobs who violate Clauser-Horne-Shimony-Holt (CHSH) Bell inequality single Alice. show do not whose ent...

The development and wide application of quantum technologies highly depend on the capacity communication channels distributing entanglement. Space-division multiplexing (SDM) enhanced channel capacities in classical telecommunication bears potential to transfer idea using current infrastructure. Here, we demonstrate an SDM polarization-entangled photons over a 411m long 19-core multicore fiber ...

We present an investigation of the $CHSH$ inequality within a relativistic quantum field theory model built up with pair free massive scalar fields $(\varphi_A, \varphi_B)$ where, as it is customary, indices $(A,B)$ refer to Alice and Bob, respectively. A set bounded Hermitian operators introduced by making use Weyl operators. type correlator constructed evaluated in Fock vacuum means canonical...

Recently the authors of Phys. Rev. Lett. 125, 090401 (2020) considered following scenario: Alice and Bob each have half a pair entangled qubit states. measures his then passes part to second who again, so on. The goal is maximize number Bobs that can an expected violation Clauser-Horne-Shimony-Holt (CHSH) inequality with single Alice. By taking maximally pure two-qubit state $|\ensuremath{\phi}...