2010/06/30 by Alastair Kay · 36 citations
Computer Science · Mathematics · Physics and Astronomy · #Class (philosophy) #Computer science #Diagonal #Entanglement witness #Mathematics #Multipartite entanglement #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #Qubit #Squashed entanglement #Transpose #W state #quant-ph
paper · pdf · doi:10.1103/physreva.83.020303
published in Physical Review A 83(2) (American Physical Society) · 4 pages, 2 figures. v2: minor improvements. v3: negative sign corrected
arxiv created 2010/07/07 · openalex publication_date 2011/02/22 · arxiv updated 2011/02/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a broad class of N-qubit Greenberger-Horne-Zeilinger (GHZ)-diagonal states such that nonpositivity under the partial transpose operation is necessary and sufficient for the presence of entanglement, including many naturally arising instances such as dephased GHZ states. Furthermore, our proof directly leads to an entanglement witness which saturates this bound. The witness is applied to thermal GHZ states to prove that the entanglement can be extremely robust to system imperfections.