We discuss under which conditions multipartite entanglement in mixed quantum states can be characterized only in terms of two-point connected cor- relation 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 cor- relations in each possible decomposition of the density matrix, or when the operators that enter in the correlations are (semi-)positive/negative defined
Can multipartite entanglement be characterized by two-point connected correlation functions?
Luca Lepori
;Andrea Trombettoni;Domenico Giuliano;
2023-01-01
Abstract
We discuss under which conditions multipartite entanglement in mixed quantum states can be characterized only in terms of two-point connected cor- relation 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 cor- relations in each possible decomposition of the density matrix, or when the operators that enter in the correlations are (semi-)positive/negative definedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.