Superposition of macroscopically distinct states means large multipartite entanglement

TL;DR

This paper establishes a link between superpositions of macroscopically distinct states and large multipartite entanglement, showing that such superpositions imply significant entanglement and sensitivity to measurements.

Contribution

It demonstrates that superpositions of macroscopically distinct states necessarily entail large multipartite entanglement across various measures.

Findings

Superpositions of macroscopically distinct states imply large multipartite entanglement.

States with such superpositions are highly sensitive to single-particle measurements.

The results connect macroscopic quantum superpositions with entanglement properties.

Abstract

We show relations between superposition of macroscopically distinct states and entanglement. These relations lead to the important conclusion that if a state contains superposition of macroscopically distinct states, the state also contains large multipartite entanglement in terms of several measures. Such multipartite entanglement property also suggests that if a state contains superposition of macroscopically distinct states, a measurement on a single particle drastically changes the state of macroscopically many other particles, as in the case of the N-qubit GHZ state.