  Using dyonic solutions in the type IIA superstring theory on Calabi-Yau
manifolds, we reconsider the study of black objects and quantum information
theory using string/string duality in six dimensions. Concretely, we relate
four-qubits with a stringy quaternionic moduli space of type IIA
compactification associated with a dyonic black solution formed by black holes
(BH) and black 2-branes (B2B) carrying 8 electric charges and 8 magnetic
charges. This connection is made by associating the cohomology classes of the
heterotic superstring on T^{4} to four-qubit states. These states are
interpreted in terms of such dyonic charges resulting from the quaternionic
symmetric space \frac{SO(4,4)}{SO(4)\times SO(4)} corresponding to a N=4 sigma
model superpotential in two dimensions. The superpotential is considered as a
functional depending on four quaternionic fields mapped to a class of Clifford
algebras denoted as Cl_{0,4}. A link between such an algebra and the cohomology
classes of T^4 in heterotic superstring theory is also given.
