26 research outputs found
Quantum Correlations in Multipartite Quantum Systems
We review some concepts and properties of quantum correlations, in particular
multipartite measures, geometric measures and monogamy relations. We also
discuss the relation between classical and total correlationsComment: to be published as a chapter of the book "Lectures on general quantum
correlations and their applications" edited by F. Fanchini, D. Soares-Pinto,
and G. Adesso (Springer, 2017
The sudden change phenomenon of quantum discord
Even if the parameters determining a system's state are varied smoothly, the
behavior of quantum correlations alike to quantum discord, and of its classical
counterparts, can be very peculiar, with the appearance of non-analyticities in
its rate of change. Here we review this sudden change phenomenon (SCP)
discussing some important points related to it: Its uncovering,
interpretations, and experimental verifications, its use in the context of the
emergence of the pointer basis in a quantum measurement process, its appearance
and universality under Markovian and non-Markovian dynamics, its theoretical
and experimental investigation in some other physical scenarios, and the
related phenomenon of double sudden change of trace distance discord. Several
open questions are identified, and we envisage that in answering them we will
gain significant further insight about the relation between the SCP and the
symmetry-geometric aspects of the quantum state space.Comment: Lectures on General Quantum Correlations and their Applications, F.
F. Fanchini, D. O. Soares Pinto, and G. Adesso (Eds.), Springer (2017), pp
309-33
Predominance of entanglement of formation over quantum discord under quantum channels
We present a study of the behavior of two different figures of merit for
quantum correlations, entanglement of formation and quantum discord, under
quantum channels showing how the former can, counterintuitively, be more
resilient to such environments spoiling effects. By exploiting strict
conservation relations between the two measures and imposing necessary
constraints on the initial conditions we are able to explicitly show this
predominance is related to build-up of the system-environment correlations.Comment: 7 pages, 5 figures, RevTeX