arXiv subjects
Publications and source records attributed to D. Malafarina.
We investigate a possible way of establishing a parallel between the third law of black hole mechanics, and the strong version of the third law of thermodynamics. We calculate the surface gravity and area for a naked singular null surface in the Gamma-metric and explain in what sense this behaviour violates thermodynamics.
The general exact solution of the Einstein-matter field equations describing spherically symmetric shells satisfying an equation of state in closed form is discussed under general assumptions of physical reasonableness. The solutions split into two classes: a class of "astro-physically interesting" solutions describing "ordinary" matter with positive density and pressure, and a class of "phantom-like" solutions with positive density but negative active gravitational mass, which can also be of interest in several "very strong fields" regimes. Known results on linear-barotropic equations of state are recovered as particular cases.
A new, globally regular model describing a static, non spherical gravitating object in General Relativity is presented. The model is composed by a vacuum Weyl--Levi-Civita special field - the so called gamma metric - generated by a regular static distribution of mass-energy. Standard requirements of physical reasonableness such as, energy, matching and regularity conditions are satisfied. The model is used as a toy in investigating various issues related to the directional behavior of naked singularities in static spacetimes and the blackhole (Schwarschild) limit.