Quantum mechanics based on real numbers: A consistent description

Abstract:Complex numbers play a crucial role in quantum mechanics. However, their necessity remains debated: whether they are fundamental or merely convenient. Recently, it was shown that any real-number quantum theory satisfying certain postulates can be falsified with multipartite experiments. In this Letter we show that a physically motivated postulate about composite quantum systems allows us to construct quantum mechanics based on real numbers that reproduces predictions for all multipartite quantum experiments. Thus, we argue that real-valued quantum mechanics cannot be falsified, and therefore the use of complex numbers is a matter of convenience.

arXiv:2503.17307 [quant-ph]

(or arXiv:2503.17307v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2503.17307 Focus to learn more arXiv-issued DOI via DataCite

Phys. Rev. Lett. 136, 240202, June 18, 2026

https://doi.org/10.1103/4k13-sdjh Focus to learn more DOI(s) linking to related resources

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