Geometrical interpretation of solutions of certain PDEs.
Geometrical modeling of material aging.
Geometrie a fyzika
Geometrodynamics of some non-relativistic incompressible fluids.
In some previous papers [1, 2] we proposed a geometric formulation of continuum mechanics, where a continuous body is seen as a suitable differentiable fiber bundle C on the Galilean space-time M, beside a differential equation of order k, Ek(C), on C and the assignement of a frame Psi on M. This approach allowed us to treat continuum mechanics as a unitary field theory and to consider constitutive and dynamical properties in a more natural way. Further, the particular intrinsic geometrical framework...
Geometrodynamics of wormholes
Gli universi ipersferici, il gruppo conforme ed il campo gravitazionale di Newton.
Global existence of large amplitude solutions for nonlinear massless Dirac equation
Global existence of solutions of the Einstein-Boltzmann equation in the spatially homogeneous case
Global Waves with Non-Positive Energy in General Relativity
2000 Mathematics Subject Classification: 35Lxx, 35Pxx, 81Uxx, 83Cxx.The theory of the waves equations has a long history since M. Riesz and J. Hadamard. It is impossible to cite all the important results in the area, but we mention the authors related with our work: J. Leray [34] and Y. Choquet-Bruhat [9] (Cauchy problem), P. Lax and R. Phillips [33] (scattering theory for a compactly supported perturbation), L. H¨ ormander [27] and J-M. Bony [7] (microlocal analysis). In all these domains, V. Petkov has...
Gravitational ionization : periodic orbits of binary systems perturbed by gravitational radiation
Gravitational lensing from a spacetime perspective.
Gravitational lensing in astronomy.
Gravitational radiation from accreting neutron stars
Neutron stars may emit steady gravitational wave signals that will be among the first kinds of gravitational wave signals that the new generation of interferometric detectors will search for. I consider here the possibility that accreting neutron stars may be driven into the steady emission of gravitational waves. I estimate the amplitudes that the waves may have if the accretion takes place at the Eddington limit, such as may happen when a neutron star spirals inside a giant star in the endphase...
Gravitational scattering of electromagnetic field by Schwarzschild black-hole
Gravitational waveforms from spinning objects
According to general relativity, a binary consisting of spinning bodies will precess due to spin-orbit and spin-spin coupling. The corresponding modulation of its gravitational waves might be a serious problem for detecting such waves with simple post-Newtonian templates. A new family of templates that takes into account the complications arising from the orbital precession is proposed and its application and performance are discussed.
Gravitational waves from coalescing binaries: a hierarchical signal detection strategy
The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template waveforms (i.e., a one step search) is used. We present, in this paper, an alternative method which is a hierarchical search strategy involving two template banks. We show that the computational power required by such a two step search, for an on-line detection of the one parameter family of Newtonian signals, is 1/8 of that required when an on-line one...
Gravitational-wave data analysis. Formalism and sample applications: the Gaussian Case.
Gravity, strings, modular and quasimodular forms
Modular and quasimodular forms have played an important role in gravity and string theory. Eisenstein series have appeared systematically in the determination of spectrums and partition functions, in the description of non-perturbative effects, in higher-order corrections of scalar-field spaces, ...The latter often appear as gravitational instantons i.e. as special solutions of Einstein’s equations. In the present lecture notes we present a class of such solutions in four dimensions, obtained by...
Ground states of supersymmetric matrix models
We consider supersymmetric matrix Hamiltonians. The existence of a zero-energy bound state, in particular for the model, is of interest in M-theory. While we do not quite prove its existence, we show that the decay at infinity such a state would have is compatible with normalizability (and hence existence) in . Moreover, it would be unique. Other values of , where the situation is somewhat different, shall also be addressed. The analysis is based on a Born-Oppenheimer approximation. This seminar...
Groupes conformes en relativité générale