Quantum Entanglement - Can Reality Really be this Weird?

Abstract

*Special Relativity places severe constraints on any possibility for faster-than-light (FTL) phenomenon. There are four hopes for FTL; warp drive via General Relativity Theory (GRT), wormholes via GRT, tachyons, and quantum mechanics. This talk focuses on why quantum mechanics makes the list. The nonlocal nature of matter demonstrates correlations between distant events that cannot be explained by current concepts of causality. For two classical events to be correlated, either one causes the other, or both possess a common cause in their past light cones. Neither kind of causality can explain the correlations observed in entangled quantum systems. Reality seems to support a third mysterious type of causality, with an essential spacelike nature, but direct spacelike causality should be impossible as it would lead to temporal paradox. The two concepts of classical causality, timelike causes and common cause, are presented along with a review of the EPR experiment showing that something like spacelike causality exists between the distant parts of an entangled quantum system. Bell’s Inequality shows that the EPR correlations cannot be attributed to common causes. Gisin’s EPR-Relativity experiment shows that timelike causes cannot explain the EPR correlations either. The metaphor of Quantum Tic-Tac-Toe is used to show a third type of causality applicable only to quantum situations. This third type of causality is an indirect spacelike cause acting through multiple classical realities, permitting FTL but prohibiting temporal paradox. I. Introduction HIS paper considers the issue of causality in entangled quantum systems. The Background section reviews the two classical notions of causality, EPR type entanglements, and Special Relativity. The Common Cause section reviews Bell’s Inequality theorem and shows how this type of causality cannot explain the correlations seen in entangled systems. The Einsteinian Causality section reviews Gisin’s experiment demonstrating that time-like causality cannot explain these correlations either. Gisin’s conclusion is that quantum systems support a new mysterious 3 rd type of causality. The Quantum Causality section introduces a situation in Quantum Tic-Tac-Toe that exhibits this same kind of causality