Quantum Measurement Without Collapse or Many Worlds: The Branched Hilbert Subspace Interpretation

Wang, Xing M. (2025) Quantum Measurement Without Collapse or Many Worlds: The Branched Hilbert Subspace Interpretation. [Preprint]

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Official URL: https://arxiv.org/abs/2504.14791

Abstract

The interpretation of quantum measurements remains contested between collapse-based frameworks like the Copenhagen Interpretation and no-collapse approaches like the Many-Worlds Interpretation (MWI). We propose the Branched Hilbert Subspace Interpretation (BHSI) as a minimalist alternative that preserves unitarity while avoiding both wavefunction collapse and ontological excess. BHSI models measurement as the unitary branching of a system's local Hilbert space into decoherent subspaces, formalized through causal state updates using branching and disengaging operators. Unlike MWI, BHSI avoids parallel worlds by maintaining a single-world ontology in which branching is confined to observable subspaces; unlike Copenhagen, it eliminates collapse while recovering the Born rule through branch weights. Through physically meaningful subspace records, the framework resolves quantum paradoxes such as particle-wave duality, Wigner and his friend, black hole radiation, etc. It remains consistent with interference patterns, entanglement correlations, and information preservation. By comparing BHSI with QBism, Relational Quantum Mechanics, and modal interpretations, as well as analyzing quantum teleportation (where locally decoherent Hilbert subspaces are observed), we demonstrate its advantages as a causally sound and empirically grounded approach that reconciles unitary evolution with definite measurement outcomes without metaphysical proliferation.

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Item Type:

Preprint

Creators:

Creators	Email	ORCID
Wang, Xing M.	shermanw2009@gmail.com	0000-0001-8673-925X

Keywords:

branched Hilbert subspaces, Bohmian Mechanics, Copenhagen Interpretation, decoherence, Many-Worlds Interpretation, No-Hiding Theorem, the Born rule, unitarity

Subjects:

General Issues > Philosophers of Science
Specific Sciences > Physics > Quantum Mechanics

Depositing User:

Dr. Xing M. Wang

Date Deposited:

16 May 2025 12:58

Last Modified:

16 May 2025 12:58

Item ID:

25332

Official URL:

https://arxiv.org/abs/2504.14791