2019/01/08 by Xiaoyu Chen, Chen, Xiao-yu, Li-zhen Jiang +1
Chemistry · Computer Science · #FOS: Physical sciences #Molecular spectroscopy and chirality #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.1901.02312
openalex publication_date 2019/01/08 · openalex created_date 2019/01/25 · openalex updated_date 2026/07/28
With a two step optimization method of entanglement witness, we analytically propose a set of necessary and sufficient entanglement criteria for four qubit symmetric Greenberger-Horne-Zeilinger (GHZ) diagonal states. The criterion set contains four criteria. Two of them are linear with density matrix elements. The other two criteria are nonlinear with density matrix elements. The criterion set has a nest structure. A proper subset of the criteria is necessary and sufficient for the entanglement of a proper subset of the states. We illustrate the nest structure of criterion set with the general Werner state set and its superset the highly symmetric GHZ diagonal state set, they are subsets of the symmetric GHZ diagonal state set.