Converting multilevel nonclassicality into genuine multipartite entanglement

Bartosz Regula, Marco Piani, Marco Cianciaruso, Thomas R. Bromley, Alexander Streltsov, Gerardo Adesso

Published 2017-04-13Version 1

Nonclassicality in the form of quantum superposition can be related to entanglement in several frameworks, where such nonclassicality becomes the necessary and sufficient ingredient to generate entanglement under some natural interactions. Here we extend previous studies by presenting a general formalism for the conversion of nonclassicality into genuine multipartite entanglement, showing that a faithful unitary conversion between the two resources is always possible. Specializing to quantum coherence between the levels of a single quantum system as an instance of nonclassicality, we introduce explicit protocols for such a mapping. We further show that the conversion relates multilevel coherence and multipartite entanglement not only qualitatively, but also quantitatively, restricting the amount of entanglement achievable in the process and in particular yielding an equality between the two resources when quantified by fidelity-based geometric measures.