  Consider a bipartite quantum system with at least one of its two components
being itself a composite system. By tracing over part of one (or both) of these
two subsystems it is possible to obtain a reduced (separable) state that
exhibits quantum correlations even if the original state of the full system is
endowed only with classical correlations. This effect, first pointed out by Li
and Luo in (2008), is of considerable interest because there is a growing body
of evidence suggesting that quantum correlations in non-entangled, mixed states
may constitute a useful resource to implement non trivial information related
tasks. Here we conduct a systematic exploration of the aforementioned effect
for particular families of states of quantum systems of low dimensionality
(three qubits states). In order to assess the non-classicality of the
correlations of the reduced states we use an indicator of quantum correlations
based upon the state disturbances generated by the measurement of local
observables. We show, for a three-qubit system, that there exists a
relationship between the classical mutual information of the original
classically correlated states and the maximum quantum correlation exhibited by
the reduced states.
