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Giuseppe De Maria

Publications and source records attributed to Giuseppe De Maria.

6 recordsLinked to original sources
arXiv2026

A covariant approach to the Dirac field in LRS space-times: the case of coplanar frames

We employ the polar decomposition of the Dirac field to describe it as an effective spinorial fluid. We then construct a $(1+1+2)$ covariant formalism for the Dirac field that avoids the introduction of tetrad fields and Clifford matrices. Within this framework, we analyze the conditions under which a self-gravitating Dirac field can be consistently embedded in Locally Rotationally Symmetric (LRS) space-times of types I, II, and III. In accordance with the LRS symmetry requirements, we extend a previous work by assuming that the velocity and spin vector fields of the Dirac field lie in the planes defined pointwise by the generators of the time-like and space-like congruences, which underlie the $(1+1+2)$ decomposition. We present some analytical and numerical solutions to illustrate the applicability of the proposed framework.

gr-qc↗
arXiv2026

Dirac Fields in Hydrodynamic Form and their Thermodynamic Formulation

We consider the theory of spinor fields written in polar form and we re-express it in terms of the so-called $1\!+\!1\!+\!2$ covariant splitting: after this is done for the basic kinematic variables, we proceed to decompose the dynamical equations, both for the case of the Dirac differential field equations and for the case of the energy density tensor. As an explicit example of a real physical application we deal with the hydrogen atom, superconductivity and an analogy with the van der Waals gas.

math-ph↗
arXiv2026

Spin-dependent neutrino oscillations in torsion backgrounds: A quantum-field-theoretic analysis

We study neutrino mixing in a background with spacetime torsion within the quantum-field-theoretic formulation of flavor oscillations. Working in the Einstein--Cartan framework and neglecting curvature, we quantize Dirac fields in constant and linearly time-dependent axial-torsion backgrounds. A constant spatial torsion component lifts the degeneracy between the two spin orientations through spin-dependent effective masses and energies. In quantum field theory this splitting modifies not only the oscillation frequencies but also the amplitudes, because the Bogoliubov coefficients entering the flavor operators depend on spin. The effect is largest at low momentum when the torsion scale is comparable to the neutrino masses, while a dominant torsion term suppresses the relative mass splittings and can inhibit flavor conversion. We also discuss the induced spin dependence of the Dirac $CP$ asymmetry and of the condensate densities in the flavor vacuum. The results identify nonrelativistic neutrinos as the natural regime in which the difference between the field-theoretic and quantum-mechanical descriptions is most pronounced.

hep-ph↗
arXiv2025

A covariant approach to the Dirac field in LRS space-times

We use the polar decomposition to describe the Dirac field in terms of an effective spinorial fluid. After reformulating all covariant equations in ``spinorial'' signature $(+ -- )$, we develop a $(1+1+2)$ covariant approach for the Dirac field that does not require the use of tetrad fields or Clifford matrices. By identifying the velocity and spin fields as the generators of time-like and space-like congruences, we examine the compatibility of a self-gravitating Dirac field with Locally Rotationally Symmetric space-times of types I, II, and III. We provide illustrative examples to demonstrate the effectiveness of our construction.

gr-qc↗
arXiv2024

Quantum Field Theory of neutrino mixing in spacetimes with torsion

In the framework of quantum field theory, we analyze the neutrino oscillations in the presence of a torsion background. We consider the Einstein-Cartan theory and we study the cases of constant torsion and of linearly time dependent torsion. We derive new neutrino oscillation formulae which are depending on the spin orientation. Indeed the energy splitting induced by the torsion influences oscillation amplitudes and frequencies. This effect is maximal for values of torsion of the same order of the neutrino masses and for very low momenta, and disappears for large values of torsion. Moreover, neutrino oscillation is inhibited for intensities of torsion term much larger than neutrino masses and momentum. The modifications induced by torsion on the $CP$-asymmetry has been also presented. Future experiments, such as PTOLEMY, could provide insights into the effect shown here.

hep-ph↗