Nonclassicality without entanglement enables bit commitment

TL;DR

This paper demonstrates that in probabilistic theories lacking entanglement but exhibiting local non-classicality, secure bit commitment protocols can be constructed, expanding understanding beyond quantum entanglement-based security.

Contribution

It introduces a convex framework applicable to various probabilistic theories and proves the existence of exponentially secure bit commitment protocols without entanglement.

Findings

Secure bit commitment is possible without entanglement in certain theories.

The framework applies to quantum, classical, and other probabilistic theories.

Security increases exponentially with the number of systems used.

Abstract

We investigate the existence of secure bit commitment protocols in the convex framework for probabilistic theories. The framework makes only minimal assumptions, and can be used to formalize quantum theory, classical probability theory, and a host of other possibilities. We prove that in all such theories that are locally non-classical but do not have entanglement, there exists a bit commitment protocol that is exponentially secure in the number of systems used.