Entanglement without Quantum Mechanics: Operational Constraints on the Quantum Signature
quant-ph
Submitted: 2025-12-16
Updated: 2026-09-16
Comments: 10 pages, 5 figures. Published version
Journal ref: Phys. Rev. Research 8, 033313 (2026)
DOI: 10.1103/xdz9-x3zj
License: http://creativecommons.org/licenses/by/4.0/
The gist: Quantum entanglement is defined as nonseparability of density operators, yet experimental phase-space statistics alone cannot distinguish classical from quantum sources, so classical data can be used
Terminology
Abstract
Quantum entanglement is defined as nonseparability of density operators, yet experimental phase-space statistics alone cannot distinguish classical from quantum sources, so classical data can be used to violate en- tanglement inequalities. Imposing uncertainty bounds, or full tomography, can map the same data onto positive, entangled density operators, yielding a hybrid regime in which classical and quantum models coincide. Thus, certifying genuine quantum entanglement requires additional tests, such as Wigner negativity, incompatibility beyond phase-space measurements, or nonlinear dynamics.
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