SUPERQUANTUM CORRELATIONS IN NON-LOCAL HIDDEN VARIABLE THEORIES A study of superquantum correlations in quantum measure theory and crypto-nonlocal theory

Quantum mechanical phenomena have a ected our lives in numerous ways. Their impact on modern technology ranges from everyday applications such as transistors, lasers and solar cells to ground breaking equipment such as Scanning-Tunneling electron microscopes. However, in spite all results in fundamental quantum theory research, various aspects of the theory are still not fully understood. This report investigates one of these challenges, namely the quantum correlations between particles in an entangled state. Early research into entangled states by Einstein, Podolsky and Rosen concluded that quantum mechanics theory is incomplete, and subsequently Bell showed that is must exhibit nonlocal correlations. This report reviews and compares two recent nonlocal hidden variable models that exhibit correlations that are more nonlocal than quantum mechanics. The rst model by Barnett, Dowker and Rideout is based on quantum measure theory, while the model by Ghirardi and Romano is a crypto-nonlocal model. Our comparison addresses the question why PR boxes, a theoretical device that allows superquantum correlations, have not been observed in nature. We argue that the type of correlations that a hidden variable models allows, are highly dependent on the type of framework used to express the model as well as on the parameters of the variables.