  A linearized variant of relative entropy is used to quantify in a unified
scheme the different kinds of correlations in a bipartite quantum system. As
illustration, we consider a two-qubit state with parity and exchange symmetries
for which we determine the total, classical and quantum correlations. We also
give the explicit expressions of its closest product state, closest classical
state and the corresponding closest product state. A closed additive relation,
involving the various correlations quantified by linear relative entropy, is
derived.
