2000/03/16 by Tohya Hiroshima, Satoshi Ishizaka
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum optics and atomic interactions #quant-ph
paper · pdf · doi:10.1103/physreva.62.044302
published as Phys. Rev. A 62, 044302 (2000)
arxiv created 2000/03/16 · openalex publication_date 2000/09/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider a special kind of mixed states---a Werner derivative, which is the state transformed by nonlocal unitary---local or nonlocal---operations from a Werner state. We show the following: (i) The amount of entanglement of Werner derivatives cannot exceed that of the original Werner state. (ii) Although it is generally possible to increase the entanglement of a single copy of a Werner derivative by local quantum operations and classical communication, the maximal possible entanglement cannot exceed the entanglement of the original Werner state. The extractable entanglement of Werner derivatives is limited by the entanglement of the original Werner state.