2008/06/30 by Chengjie Zhang, Cheng-Jie Zhang, Yan-Xiao Gong +3
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Concurrence #Entropy (arrow of time) #Mathematical analysis #Mathematical physics #Mathematics #Mixing (physics) #Observable #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #State (computer science) #Statistical physics #Upper and lower bounds #quant-ph
paper · pdf · doi:10.1103/physreva.78.042308
published as Phys. Rev. A 78, 042308 (2008) · 5 pages, 2 figures
openalex publication_date 2008/10/09 · arxiv created 2008/10/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present observable upper bounds for the squared concurrence, which are the dual inequalities of the observable lower bounds introduced by Mintert and Buchleitner [Phys. Rev. Lett. 98, 140505 (2007)] and Aolita et al. [Phys. Rev. A 78, 022308 (2008)]. These bounds can be used to estimate entanglement for arbitrary experimental unknown finite-dimensional states by a few experimental measurements on a twofold copy \ensuremathρ\ensuremath\bigotimes\ensuremathρ of the mixed states. Furthermore, the degree of mixing for a mixed state and some properties of the linear entropy also have certain relations with the upper and lower bounds of its squared concurrence.