CHSH Inequality Research Papers - Academia.edu (original) (raw)

We show that the complementarity relation between dichotomic observables leads to the monogamy of Bell inequality violations. We introduce a simple condition for the squares of expectation values of complementary observables that is... more

We show that the complementarity relation between dichotomic observables leads to the monogamy of Bell inequality violations. We introduce a simple condition for the squares of expectation values of complementary observables that is satisfied by all physical states. This condition is used to study multi-qubit correlation inequalities involving two settings per observer. In contrast with the two-qubit case a rich structure of possible violation patterns is shown to exist in the multipartite scenario.

Elementary particles such as electrons and photons can be entangled in pairs, meaning that while they appear to have separate lives they share a quantum-level interaction that defies a straightforward physical interpretation. In the case... more

Elementary particles such as electrons and photons can be entangled in pairs, meaning that while they appear to have separate lives they share a quantum-level interaction that defies a straightforward physical interpretation. In the case of electrons, this entanglement can manifest itself in spin states describing two particles that may be separated by enormous distances, yet somehow remain together in the same state. Consequently, a measurement performed on one electron’s spin appears to instantaneously determine the spin of its partner, even if it’s on the other side of the universe. This strange phenomenon, which has been verified many times in carefully conducted laboratory experiments, appears to violate the notions of objective reality and locality—the classical belief that nothing can travel faster than the speed of light.

In this Letter, we explore the possibility of developing Bell inequalities predicated on models using a single Local Hidden Variable (s-LHV), a strict subset of general LHV models. Because of the less strenuous constraints imposed by... more

In this Letter, we explore the possibility of developing Bell inequalities predicated on models using a single Local Hidden Variable (s-LHV), a strict subset of general LHV models. Because of the less strenuous constraints imposed by s-LHV models, we were able to derive a contingent Bell inequality in analogy to the CHSH inequality, but which does not require bounding of measurement statistics. Following this, we show by explicit example that there are cases of states that rule out s-LHV models by violating our inequality, but which nonetheless have a multivariate LHV model. Even so, we show how merely ruling out s-LHV models is still sufficient to allow for fully device independent quantum key distribution (QKD) and entanglement witnessing. This being the case, our inequality illustrates two things. First, it makes fully device-independent QKD on continuous variables substantially more straightforward. Second, it shows how the degree of correlation needed to demonstrate device-inde...

The logical foundations of Bell's inequality are reexamined. We argue that the form of the reality condition that underpins Bell's inequality comes from the requirement of solving the quantum measurement problem. Hence any... more

The logical foundations of Bell's inequality are reexamined. We argue that the form of the reality condition that underpins Bell's inequality comes from the requirement of solving the quantum measurement problem. Hence any violation of Bell's inequality necessarily implies nonlocality because of the measurement problem. The differences in the implications of deterministic and stochastic formulations of Bell's inequality are highlighted. The reality condition used in Bell's inequality is shown to be a generalisation of Einstein's later form of realism.

We prove here a version of Bell's Theorem that is simpler than any previous one. The contradiction of Bell's inequality with Quantum Mechanics in the new version is not cured by non-locality so that this version allows one to single out... more

We prove here a version of Bell's Theorem that is simpler than any previous one. The contradiction of Bell's inequality with Quantum Mechanics in the new version is not cured by non-locality so that this version allows one to single out classical realism, and not locality, as the common source of all false inequalities of Bell's type.

Elementary particles such as electrons and photons can be entangled in pairs, meaning that while they appear to have separate lives they share a quantum-level interaction that defies a straightforward physical interpretation. In the case... more

Elementary particles such as electrons and photons can be entangled in pairs, meaning that while they appear to have separate lives they share a quantum-level interaction that defies a straightforward physical interpretation. In the case of electrons, this entanglement can manifest itself in spin states describing two particles that may be separated by enormous distances, yet somehow remain together in the same state. Consequently, a measurement performed on one electron’s spin appears to instantaneously determine the spin of its partner, even if it’s on the other side of the universe. This strange phenomenon, which has been verified many times in carefully conducted laboratory experiments, appears to violate the notions of objective reality and locality—the classical belief that nothing can travel faster than the speed of light.