Realism, Non-Contextuality, Local Causality, Entanglement

William Sulis

Several decades of theory and experiment into EPR correlations have led to the widely held belief that reality is non-local, in spite of the fact that this violates special relativity. To date, no experiment has shown a violation of special relativity, and EPR experiments do not demonstrate the existence of superluminal information exchange, merely correlations which violate certain inequalities. Every “loophole” in these hidden variable theories has been thought plugged. However, there is much confusion in the literature due to conflation of the terms ‘locality”, “realism”, “hidden variables”, “non-contextuality”. The presence of local hidden variables is thought to necessarily lead to a Kolmogorov probability structure (hence non-contextuality), but this is an assumption, one which is not true in general once context effects are taken into account. Treated as an observational theory, several authors have shown no incompatibility between quantum mechanics and locality, and that the Bell scenario is actually about whether reality is contextual. This paper proposes a descriptive theory by assuming a generated reality (following Whitehead’s Process Theory) which can violate the principle of continuity and possess non-Kolmogorov probability structure, and reproduce the results of non-relativistic quantum mechanics, while allowing only causally local information exchange, without hidden variables. A generated reality is thus compatible with both quantum mechanics and special relativity, reproducing all of the results expected from quantum mechanics while still maintaining causally local realism. This process model thus appears to be an ideal candidate for developing theories for the unification of quantum mechanics and general relativity.

Gregg S. Jaeger

Debashis Saha

The descriptions of the quantum realm and the macroscopic classical world di�er signi �cantly not only in their mathematical formulations, but also in their foundational concepts and philosophical consequences. The assumptions of local realism, non-contextuality and macroscopic realism (macro-realism) along with the quantum mechanical violations of these assumptions are discussed. A complete generalization is provided of Wigner's argument inferring quantum nonlocality, originally restricted for the EPR-Bohm entangled state, based on assuming joint probability distributions for all the relevant dichotomic observables. Such Generalized Wigner Inequality (GWI) turns out to be the N-partite local realist inequality which is violated by quantum mechanics for all pure entangled states for any N. We then exploit the non-trivial manifestation of quantum non-locality via local contextuality on three qubit system. Here, we propose an experimental scheme to realize this feature by deriving a new local realist inequality. The way quantum entanglement can be used for global contextual value assigning is discussed in a quantum pseudo-telepathy game. In the second part of this report, we formulate Leggett-Garg inequality (LGI) in terms of joint probability and demonstrate its quantum mechanical violation for two state oscillation, which is initial state dependent, unlike the case of standard LGI. It has been shown that, the newly formulated LGI reveals robustness against unsharp measurement for testing compatibility between macro-realism and quantum mechanics. Finally we show that, the recently proposed No-signaling in time condition, contradicts with quantum mechanical predictions for any degree of unsharpness in measurement.

Michael L. G. Redhead