Several foundational and information theoretic implications of Bell's theorem

TL;DR

This paper reviews the foundational and information theoretic implications of Bell's theorem, highlighting its role in quantum nonlocality, the violation of local realism, and its applications in information protocols.

Contribution

It provides a comprehensive overview of Bell's inequality, its derivations, and its significance in quantum foundations and information theory.

Findings

Bell's inequality can be derived from various assumptions.

Quantum mechanics violates Bell's inequality, indicating nonlocality.

Bell's theorem has applications in quantum information protocols.

Abstract

In 1935, Albert Einstein and two colleagues, Boris Podolsky and Nathan Rosen (EPR) developed a thought experiment to demonstrate what they felt was a lack of completeness in quantum mechanics. EPR also postulated the existence of more fundamental theory where physical reality of any system would be completely describe by the variables/states of that fundamental theory. This variable is commonly called hidden variable and the theory is called hidden variable theory (HVT). In 1964, John Bell proposed an empirically verifiable criterion to test for the existence of these HVTs. He derived an inequality, which must be satisfied by any theory that fulfill the conditions of locality and reality} He also showed that quantum mechanics, as it violates this inequality, is incompatible with any local-realistic theory. Later it has been shown that Bell's inequality can be derived from different set of assumptions and it also find applications in useful information theoretic protocols. In this review we will discuss various foundational as well as information theoretic implications of Bell's inequality. We will also discuss about some restricted nonlocal feature of quantum nonlocality and elaborate the role of Uncertainty principle and Complementarity principle in explaining this feature.