CLASSICALITY WITNESS FOR TWO-QUBIT STATES
2012 ◽
Vol 10
(03)
◽
pp. 1250028
◽
Keyword(s):
In the last few years one realized that if the state of a bipartite system can be written as ∑i,j pij|ai〉〈ai| ⊗ |bj〉〈bj|, where {|ai〉} and {|bj〉} form orthonormal basis for the subsystems and {pij} 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.
2016 ◽
Vol 115
(1)
◽
pp. 10003
◽
1980 ◽
Vol 29
(3-4)
◽
pp. 143-160
◽
1972 ◽
Vol 9
(02)
◽
pp. 457-461
◽
2015 ◽
Vol 13
(04)
◽
pp. 1550029
◽
2002 ◽
Vol 31
(5)
◽
pp. 271-282
2019 ◽
Vol 22
(03)
◽
pp. 1950022
◽