The study of classical and quantum correlations in bipartite and multipartite
systems is crucial for the development of quantum information theory. Among the
quantifiers adopted in tripartite systems, the genuine tripartite quantum
discord (GTQD), estimating the amount of quantum correlations shared among all
the subsystems, plays a key role since it represents the natural extension of
quantum discord used in bipartite systems. In this paper, we derive an
analytical expression of GTQD for three-qubit systems characterized by a
subclass of symmetrical X-states. Our approach has been tested on both GHZ and
maximally mixed states reproducing the expected results. Furthermore, we
believe that the procedure here developed constitutes a valid guideline to
investigate quantum correlations in form of discord in more general
multipartite systems.Comment: 13 pages, 4 figures. v3: Added some references and corrected some
typo
