Can multipartite entanglement be characterized by two-point connected correlation functions?

Lepori, Luca and Trombettoni, Andrea and Giuliano, Domenico and Kombe, Johannes and Yago Malo, Jorge and Daley, Andrew J and Smerzi, Augusto and Luisa Chiofalo, Maria (2023) Can multipartite entanglement be characterized by two-point connected correlation functions? Journal of Physics A: Mathematical and Theoretical, 56 (30). 305302. ISSN 1751-8113 (https://doi.org/10.1088/1751-8121/acdd36)

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Abstract

We discuss under which conditions multipartite entanglement in mixed quantum states can be characterized only in terms of two-point connected correlation functions, as it is the case for pure states. In turn, the latter correlations are defined via a suitable combination of (disconnected) one- and two-point correlation functions. In contrast to the case of pure states, conditions to be satisfied turn out to be rather severe. However, we were able to identify some interesting cases, as when the point-independence is valid of the one-point correlations in each possible decomposition of the density matrix, or when the operators that enter in the correlations are (semi-)positive/negative defined.

ORCID iDs

Lepori, Luca, Trombettoni, Andrea, Giuliano, Domenico, Kombe, Johannes, Yago Malo, Jorge, Daley, Andrew J ORCID logoORCID: https://orcid.org/0000-0001-9005-7761, Smerzi, Augusto and Luisa Chiofalo, Maria;