VIGNOLO , Stefano

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A new geometrical framework for tetrad-af ne formulation of gravity, pure or coupled with Yang–Mills elds, is proposed. After analyzing the geometrical prop- erties of the new mathematical setting, eld equations are deduced from a varia- tional principle in the Poincaré–Cartan formalism. A generalized Noether Theorem is stated and classical...

A unified formulation of rigid body dynamics based on Gauss principle is proposed. The Lagrange, Kirchhoff and Newton–Euler equations are seen to arise from different choices of the quasicoordinates in the velocity space. The group-theoretical aspects of the method are discussed.

A new variational principle for General Relativity, based on an action functional involving both the metric tensor and the affine connection as independent degrees of freedom is presented. The resulting extremals are seen to be pairs consisting of a Ricci flat metric and of the associated Riemannian connection. An application to Kaluza's theory...

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In this paper, we consider the torsional completion of gravitation for an underlying background filled with Dirac fields, applying it to the problem of neutrino oscillations: we discuss the effects of the induced torsional interactions as corrections to the neutrino oscillations mechanism.

We study Weyssenhoff spin fluids in Bianchi type-I cosmological models, within the framework of torsional f(R)-gravity; the resulting field equations are derived and discussed in both Jordan and Einstein frames, clarifying the role played by the spin and the non-linearity of the gravitational Lagrangian f(R) in generating the torsional...

The Cauchy problem for metric-affine f(R)-gravity à la Palatini and with torsion, in presence of perfect fluid matter acting as source, is discussed following the well-known Bruhat prescriptions for General Relativity. The problem results well-formulated and well-posed when the perfect-fluid form of the stress-energy tensor is preserved under...

In the framework of J-bundles a vielbein formulation of unified Einstein--Maxwell theory is proposed. In the resulting scheme, field equations matching the gravitational and electromagnetic fields are derived by constraining a 5-dimensional variational principle. No dynamical scalar field in involved.