On the geometry of null cones in Einstein-vacuum spacetimes
On the quadric CMC spacelike hypersurfaces in Lorentzian space forms
We deal with complete spacelike hypersurfaces immersed with constant mean curvature in a Lorentzian space form. Under the assumption that the support functions with respect to a fixed nonzero vector are linearly related, we prove that such a hypersurface must be either totally umbilical or isometric to a hyperbolic cylinder of the ambient space.
Onde di discontinuità gravitazionali in relatività generale
Post-Newtonian approximation in the test particle limit
Gravitational radiation from a small mass particle orbiting a massive black hole can be analytically studied to a very high order in the post-Newtonian expansion. Thus it gives us useful information on the evolution of a coalescing compact binary star. In this talk, I report on recent progress made in the black-hole perturbation approach.
Post-Newtonian approximations and equations of motion of general relativity
A post-Newtonian approximation scheme for general relativity is defined using the Arnowitt-Deser-Misner formalism. The scheme is applied to perfect fluids and point-mass systems. The two-body point-mass Hamiltonian is given explicitly up to the post-Newtonian order.
Post-newtonian generation of gravitational waves. II. The spin moments
Post-Newtonian hydrodynamic equations using the (3+1) formalism in general relativity
The post-Newtonian (PN) hydrodynamic equations are obtained in the (3+1) formalism, which include the 2.5PN order as the reaction due to the quadrupole gravitational radiation. These equations are valid in various slice conditions, while we adopt a kind of transverse gauge condition to determine the shift vector. In particular, we describe methods to solve the 2PN tensor potential which arises from the spatial 3-metric. Our formulaton in the PN approximation using the (3+1) formalism will be useful...
Progress towards a local expression for radiation reaction
We report on progress towards finding a local expression for radiation reaction for a particle orbiting a Kerr black hole. The Dirac-Gal'tsov approach is described. For the case of a scalar particle in a circular orbit of a Schwarzschild black hole, an explicit calculation is done via this method and shown to be in agreement with overall energy conservation. A possible approach to the case of more general orbits is also discussed.
Qualche osservazione sulle forze centrali in Relatività Ristretta
In Relatività Ristretta si caratterizzano le forze centrali per cui le orbite al finito sono necessariamente chiuse ed ellittiche, per qualunque valore dell'energia.
Quantum mechanics and coherent states on the anti-de Sitter spacetime and their Poincaré contraction
Quantum vacuum polarization at the Black-Hole horizon
Quasi-local energy-momentum and the Sen geometry of two-surfaces
We review the main ideas of the two dimensional Sen geometry and apply these concepts i. in finding the `most natural' quasi-local energy-momentum, ii. in characterizing the zero energy-momentum and zero mass configurations and iii. in finding the quasi-local radiative modes of general relativity.
Remarks on Riemannian Thermodynamics
The postulates of macroscopic thermodynamics give us the possibility to endow the set of thermodynamic states with the structure of a riemannian manifold. Two alternatives are available: the first one is to introduce on the set of thermodynamic equilibrium states a metric induced by an embedding metric space (extrinsic approach), the second one is to introduce the stability metric (intrinsic approach). Between the two choices the second one looks more promising on the basis of its capability of...
Résolution des équations aux connexions du cas antisymétrique de la théorie unitaire hypercomplexe. Application à un principe variationnel
Scattering of linear Dirac fields by a spherically symmetric Black-Hole
Shock waves and general relativity
Shock-wave explosions in general relativity
Six-dimensional considerations of Einstein's connection for the first two-classes. I: The recurrence relations in 6--UFT.
Smooth static solutions of the spherically symmetric Vlasov-Einstein system
Spherical detectors of gravitational waves
Resonant mass detectors of GWs of spherical shape constitute the fourth generation of such kind of antennae, and are scheduled to start operation in the near future. In this communication I present a general description of the fundamental principles underlying the physics of this kind of detector, as well as of the motion sensor set suitable to retrieve the information generated by the incidence of a GW on the antenna.