2010/12/31 by J. Maziero, JONAS MAZIERO, R. M. Serra +1
Computer Science · Physics and Astronomy · #Basis (linear algebra) #Bipartite graph #Nonlinear system #Orthonormal basis #Quantum #Quantum Information and Cryptography #Quantum chaos and dynamical systems #State (computer science) #Witness #quant-ph #stochastic dynamics and bifurcation
paper · pdf · doi:10.1142/s0219749912500281
published as Int. J. Quant. Inf. 10, 1250028 (2012) · To appear in IJQI
arxiv created 2012/02/22 · crossref issued 2012/04/01 · crossref published 2012/04/01 · crossref published-print 2012/04/01 · openalex publication_date 2012/04/01 · crossref published-online 2012/05/24 · crossref created 2012/05/30 · arxiv updated 2012/06/04 · openalex created_date 2016/06/24 · crossref deposited 2019/08/07 · crossref indexed 2026/08/03 · openalex updated_date 2026/08/05
In the last few years one realized that if the state of a bipartite system can be written as ∑ i,j p ij |a i 〉〈a i | ⊗ |b j 〉〈b j |, where |a i 〉 and |b j 〉 form orthonormal basis for the subsystems and p ij is a probability distribution, then it possesses at most classical correlations. In this article we introduce a nonlinear witness providing a sufficient condition for classicality of correlations (absence of quantum discord) in a broad class of two-qubit systems. Such witness turns out to be necessary and sufficient condition in the case of Bell-diagonal states. We show that the witness introduced here can be readily experimentally implemented in nuclear magnetic resonance setups.