The research activity of Dott. Nakia Carlevaro, in collaboration with Dr. Giovanni Montani, deals with Unification Models and Geometrical Theories focusing on the role of Lorentz Symmetry in relation with the spontaneous compactification process of extra-dimensions. He develops an Unification Scheme based on the spontaneous Multidimensional Lorentz symmetry breaking in the 4-dimensional one plus internal symmetries (as in the usual compactification scheme). In this approach the local symmetry is associated to a gauge field which produces Yang-Mills fields after the spontaneous symmetry breaking. Starting from identifying Torsion Field as the gauge field of the 4-dimensional Lorentz Group, a Kaluza-Klein Theory is addressed. The Multidimensional scheme does not contain metric components which can reproduce non-abelian gauge fields but it deals with a Torsion Field whose extra-dimensional components generate such Young-Mills field. To this end it is important to deeply analyze the Lorentz symmetry structure in the (4+1) formulation, which is fundamental for a canonical approach to the Gravity Quantization.

One of the crucial problems of this Multidimensional Unification Scheme is the applicability of the Higgs Model. In this sense he study alternative formulations which can produce massive contributions to vector field. A specific application consists in the Kaluza-Klein implementation of the Stueckelberg Field dynamics which corresponds to an alternative formulation of the Procà model to assign a mass to an abelian vectorial boson in a renormalizzable scheme.

Beside these formulations the study of Early Universe Dynamics was addressed. In particular the attention is focused on the extension of the Isotropic and Quasi-isotropic model with correction due to the presence of Bulk Viscosity in the description of the fluid filling the space-time. He study the Universe dynamics in the asymptotic limit toward the singularity and very different behavior is found when dissipative effects are taken into account. As main result a viscosity coefficient threshold value for the validity of the two models was found and a very intense dumping of the Density Contrast contraction was observed. Furthermore he investigated, in the newtonian approximation, the extreme collapse of a spherically symmetric gas cloud in presence of Bulk Viscosity.