Results 21 to 30 of about 678,025 (58)
Dilatonic, Current-Carrying Cosmic String [PDF]
We study the implications of a scalar-tensorial gravity for the metric of an isolated self-gravitating superconducting cosmic string. These modifications are induced by an arbitrary coupling of a massless scalar field to the usual tensorial field in the gravitational Lagrangian.
arxiv +1 more source
Instant preheating mechanism and UHECR [PDF]
Top-down models assume that the still unexplained Ultra High Energy Cosmic Rays (UHECR's) are the decay products of superheavy particles. Such particles may have been produced by one of the post-inflationary reheating mechanisms and may account for a fraction of the cold dark matter.
arxiv +1 more source
Perturbed Einstein field equations using Maple [PDF]
We obtain the perturbed components of affine connection and Ricci tensor using algebraic computation. Naturally, the perturbed Einstein field equations for the vacuum can be written. The method can be used to obtain perturbed equations of the superior order.
arxiv
Ultralocality on the lattice [PDF]
It is shown that the nonlocal Dirac operator yielded by a lattice model that preserves chiral symmetry and uniqueness of fields, approaches to an ultralocal and invariant under translations operator when the size of the lattice tends to zero.
arxiv
Constrained Variational Calculus for Higher Order Classical Field Theories [PDF]
We develop an intrinsic geometrical setting for higher order constrained field theories. As a main tool we use an appropriate generalization of the classical Skinner-Rusk formalism. Some examples of application are studied, in particular, applications to the geometrical description of optimal control theory for partial differential equations.
arxiv +1 more source
Updated Limits on Visibly and Invisibly Decaying Higgs Bosons from LEP [PDF]
Talk presented at the XXIX Rencontres de Moriond, Electroweak Interactions and Unified Theories, March 12-19, 1994 ...
arxiv
Exact solutions for the spatial de Vaucouleurs and Sersic laws and related quantities [PDF]
Using the Mathematica package, we find exact analytical expressions for the so-called de-projected De Vaucouleurs and Sersic laws as well as for related spatial (3D) quantities, such the mass, gravitational potential, the total energy and the central velocity dispersion, generally involved in astronomical calculations expressed in terms of the Meijer G
arxiv +1 more source
Growing of the Inhomogeneities with Particle Production [PDF]
Perturbations in Prigogine's cosmological model with particle creation are investigated in the framework of Newtonian Theory. The necessary conditions for the density contrast to reach the non-linear regime wich is necessary to garantee structure formation at large scale are obtained.
arxiv
Evolution of the Density Contrast with Particle Production in a Gauge-Invariant Formalism [PDF]
In this work we derive the evolution equation for the density contrast considering open system cosmology, where the influence of adiabatic particle production process on the dynamic of a homogeneous and isotropic is investigated within a manifestly covariant formulation.
arxiv
Chen-Wu type model and the total energy of the universe [PDF]
The inclusion of a $\Lambda $ term, today, in the relativistic field equations is consequence of the evolution of an observational cosmology. In this work we argue the "ansatz" $\Lambda = \beta H^2 +\frac{\alpha}{R^2}$ is applicable to the total energy density of the universe, discuss some cosmological consequences and compare the growing mode of the ...
arxiv