Local and Nonlocal Contents in N-qubit generalized GHZ states

TL;DR

This paper analyzes the local and nonlocal correlations in N-qubit generalized GHZ states, providing bounds on their local content and extending previous results for two-qubit cases.

Contribution

It introduces a decomposition of correlations into local and nonlocal parts for N-qubit GHZ states and derives bounds that generalize earlier two-qubit findings.

Findings

Lower bound matches previous two-qubit results

Local content decreases rapidly with increasing N

Provides bounds on local and nonlocal correlations in GHZ states

Abstract

We investigate local contents in $N$-qubit generalized Greenberger, Horne, and Zeilinger (GHZ) states. We suggest a decomposition for correlations in the GHZ states into a nonlocal and fully local part, and find a lower and upper bound on the local content. Our lower bound reproduces the previous result for N=2 [Scarani, Phys. Rev. A. 77, 042112 (2008)] and decreases rapidly with $N$.