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arXiv · 2506.15474

Temporal Entanglement and Witnesses of Non-Classicality

Giuseppe Di Pietra·Gaurav Bhole·James Eaton·Andrew J. Baldwin·Jonathan A. Jones·Vlatko Vedral·Chiara Marletto
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Abstract

The universality of quantum theory has been questioned ever since it was proposed. Key to this long-unsolved question is to test whether a given physical system has non-classical features. Here we connect recently proposed witnesses of non-classicality, based on information-theoretic ideas, with the theory of temporal entanglement. We provide a protocol to witness the non-classicality of a system by probing it with a qubit: we show that, assuming a general conservation law, violating temporal Bell inequalities on the qubit probe implies the non-classicality of the system under investigation. We also perform proof-of-principle experimental emulations of the proposed witness of non-classicality, using a three qubit Nuclear Magnetic Resonance quantum computer. Our result is robust, as it relies on minimal assumptions, and remarkably it can be applied in a broad range of contexts, from quantum biology to quantum gravity.

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Giuseppe Di Pietra, Gaurav Bhole, James Eaton, Andrew J. Baldwin, Jonathan A. Jones, Vlatko Vedral, Chiara Marletto. 2025-06-18. Temporal Entanglement and Witnesses of Non-Classicality. https://arxiv.org/abs/2506.15474

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