Quantum physics cannot be captured by classical linear hidden variable theories even in the absence of entanglement

Fuente: arXiv
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Main Authors: Rasbi, Kawthar Al, Clark, Lewis A., Beige, Almut
Format: Preprint
Published: 2023
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author Rasbi, Kawthar Al
Clark, Lewis A.
Beige, Almut
author_facet Rasbi, Kawthar Al
Clark, Lewis A.
Beige, Almut
contents Recent experimental tests of Bell inequalities confirm that entangled quantum systems cannot be described by local classical theories but still do not answer the question whether or not quantum systems could in principle be modelled by linear hidden variable theories. In this paper, we study the quantum trajectories of a single qubit that experiences a sequence of repeated generalised measurements. It is shown that this system, which constitutes a Hidden Quantum Markov Model, is more likely to produce complex time correlations than any classical Hidden Markov Model with two output symbols. From this, we conclude that quantum physics cannot be replaced by linear hidden variable theories. Indeed, it has already been recognised that not only entanglement but also non-classical time correlations of quantum systems with quantum feedback are a valuable resource for quantum technology applications.
format Preprint
id arxiv_https___arxiv_org_abs_2310_13815
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Quantum physics cannot be captured by classical linear hidden variable theories even in the absence of entanglement
Rasbi, Kawthar Al
Clark, Lewis A.
Beige, Almut
Quantum Physics
Recent experimental tests of Bell inequalities confirm that entangled quantum systems cannot be described by local classical theories but still do not answer the question whether or not quantum systems could in principle be modelled by linear hidden variable theories. In this paper, we study the quantum trajectories of a single qubit that experiences a sequence of repeated generalised measurements. It is shown that this system, which constitutes a Hidden Quantum Markov Model, is more likely to produce complex time correlations than any classical Hidden Markov Model with two output symbols. From this, we conclude that quantum physics cannot be replaced by linear hidden variable theories. Indeed, it has already been recognised that not only entanglement but also non-classical time correlations of quantum systems with quantum feedback are a valuable resource for quantum technology applications.
title Quantum physics cannot be captured by classical linear hidden variable theories even in the absence of entanglement
topic Quantum Physics
url https://arxiv.org/abs/2310.13815