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arXiv · 2307.13218

Decoherence, Branching, and the Born Rule in a Mixed-State Everettian Multiverse

Eugene Y. S. Chua·Eddy Keming Chen
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Abstract

In Everettian quantum mechanics, justifications for the Born rule appeal to self-locating uncertainty or decision theory. Such justifications have focused exclusively on a pure-state Everettian multiverse, represented by a wave function. Recent works in quantum foundations suggest that it is viable to consider a mixed-state Everettian multiverse, represented by a (mixed-state) density matrix. Here, we develop the conceptual foundations for decoherence and branching in a mixed-state multiverse, and extend arguments for the Born rule to this setting. This extended framework provides a unification of 'classical' and 'quantum' probabilities, and additional theoretical benefits, for the Everettian picture.

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Eugene Y. S. Chua, Eddy Keming Chen. 2023-07-25. Decoherence, Branching, and the Born Rule in a Mixed-State Everettian Multiverse. https://doi.org/10.1007/s11229-025-04949-0

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