Bosonic fields in states with undefined particle numbers possess detectable non-contextuality features, plus more

Autor: Konrad Schlichtholz, Antonio Mandarino, Marek Żukowski
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: New Journal of Physics, Vol 24, Iss 10, p 103003 (2022)
Druh dokumentu: article
ISSN: 1367-2630
DOI: 10.1088/1367-2630/ac919e
Popis: The paradoxical features of quantum theory are usually formulated for fixed number of particles. While one can now find a formulation of Bell’s theorem for quantum fields, a Kochen–Specker-type reasoning is usually formulated for just one particle, or like in the case of Peres–Mermin square for two. Is it possible to formulate a contextuality proof for situation in which the numbers of particles are fundamentally undefined? We introduce a representation of the $\mathfrak{s}\mathfrak{u}(2)$ algebra in terms of boson number states in two modes that allows us to assess nonclassicality of states of bosonic fields. This representation allows to show contextuality, and is efficient to reveal violation of local realism, and to formulate entanglement indicators. A form of an non-contextuality inequality is derived, giving a bosonic Peres–Mermin square. The entanglement indicators are built with Pauli-like field observables. The non-clasicality indicators are effective. This is shown for the 2 × 2 bright squeezed vacuum state, and a recently discussed bright-GHZ state resulting from multiple three photon emissions in a parametric process.
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