Wednesday, December 19, 2012

1212.4387 (Aharon Brodutch et al.)

Vanishing quantum discord is \emph{not} necessary for
completely-positive maps
   [PDF]

Aharon Brodutch, Animesh Datta, Kavan Modi, Ángel Rivas, César A. Rodríguez-Rosario
The description of the dynamics of a system that may be correlated with its environment is only meaningful within the context of a specific framework. Different frameworks rely upon different assumptions about the initial system-environment state. We reexamine the connections between complete-positivity and quantum discord within two different sets of assumptions about the relevant family of initial states. We present an example of a system-environment state with non-vanishing quantum discord that leads to a completely-positive map. This invalidates an earlier claim on the necessity of vanishing quantum discord for completely-positive maps. In our final remarks we discuss the physical validity of each approach and discuss an additional framework relevant for quantum process tomography.
View original: http://arxiv.org/abs/1212.4387

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