1308.0901 (M. Mahdian et al.)

Quantum discord in bipartite systems based on projection measurements    [PDF]

M. Mahdian, F. Marahem

We propose a method to detect an exact quantum discord for some general bipartite quantum systems analytically. Here we show that for some density matrices, after the orthogonal projective measurement the state of the matrix will be diagonal and classic. So we can obtain the maximum amount of classical information in this case. Consequently, for these density matrices instead of using the positive operator valued measures (POVMs), projective operators can be used. Also we obtain the relation between quantum discord with relative entropy of discord for these states and show that for various examples of X-states such as on two qubit and qubit-qutrit density matrices, the relative entropy of discord is replaced by quantum discord.

View original: http://arxiv.org/abs/1308.0901