Curvature-enhanced multipartite coherence in the multiverse*

Abstract

Here, we study quantum coherence of N-partite GHZ (Greenberger-Horne-Zeilinger) and W states in the
multiverse consisting of N causally disconnected de Sitter spaces. Interestingly, N-partite coherence in-
creases monotonically as the curvature increases, while the curvature effect destroys quantum entanglement
and discord, meaning that the curvature effect is beneficial to quantum coherence and harmful to quantum
correlations in the multiverse. We find that, with the increase of n expanding de Sitter spaces, N-partite
coherence of GHZ state increases monotonically for any curvature, while quantum coherence of the W state
decreases or increases monotonically depending on the curvature. We find a distribution relationship, which
indicates that the correlated coherence of N-partite W state is equal to the sum of all bipartite correlated coherence in the multiverse. Multipartite coherence exhibits unique properties in the multiverse, which argues that it may provide some evidence for the existence of the multiverse.