Peano Baker series convergence for matrix-valued functions of bounded variation.
Perturbative quantum gravity and its relation to gauge theory.
Physics, astrophysics and cosmology with gravitational waves.
Physics of neutron star crusts.
Polyhomogeneous solutions of wave equations in the radiation regime
While the physical properties of the gravitational field in the radiation regime are reasonably well understood, several mathematical questions remain unanswered. The question here is that of existence and properties of gravitational fields with asymptotic behavior compatible with existence of gravitational radiation. A framework to study those questions has been proposed by R. Penrose (R. Penrose, “Zero rest-mass fields including gravitation”, Proc. Roy. Soc. London A284 (1965), 159-203), and developed...
Positive energy in general relativity
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
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...
Precession of the perihelion within a generalized theory for the two body problem
Sulla base di una teoria generalizzata di Meccanica Classica per il problema dei Due Corpi, recentemente formulata dall'autore, si considera la questione della precessione del perielio dei pianeti, assente nel caso Newtoniano. Si mostra come la descrizione di questo fenomeno in tale teoria generalizzata è sostanzialmente equivalente a quella offerta dalla Relatività Generale.
Principe de recollement des équations des contraintes en relativité générale
La méthode de « recollement » permettant de trouver des solutions des équations des contraintes relativistes est décrite. En particulier, on expose la méthode de Corvino-Schoen pour construire des familles de solutions sur une variété non-compacte avec géométrie prescrite sur un bout asymptotique, en insistant sur le recollement « non-localisé ». Une liste de résultats obtenus par divers auteurs à partir de telles techniques est alors fournie, incluant la question du recollement de métriques...
Probes and tests of strong-field gravity with observations in the electromagnetic spectrum.
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.
Proper homothetic vector fields in Bianchi type-I space-time.
Pseudo-Riemannian and Hessian geometry related to Monge-Ampère structures
We study properties of pseudo-Riemannian metrics corresponding to Monge-Ampère structures on four dimensional . We describe a family of Ricci flat solutions, which are parametrized by six coefficients satisfying the Plücker embedding equation. We also focus on pullbacks of the pseudo-metrics on two dimensional , and describe the corresponding Hessian structures.