Sergio del Campo

Holographic principle and the dominant energy condition for Kasner type metrics

Abstract In this Letter we study adiabatic anisotropic matter filled Bianchi type I models of the Kasner form together with the cosmological holographic bound. We find that the dominant energy condition and the holographic bound give precisely the same constraint on the scale factor parameters that appear in the metric.

(2+1)-dimensional black hole with Coulomb-like field

Abstract A (2+1)-static black hole solution with a nonlinear electric field is derived. The source to the Einstein equations is a nonlinear electrodynamics, satisfying the weak energy conditions, and it is such that the energy momentum tensor is traceless. The obtained solution is singular at the origin of coordinates. The derived electric field E ( r ) is given by E ( r )= q / r 2 , thus it has the Coulomb form of a point charge in the Minkowski spacetime. This solution describes charged (anti)-de Sitter spaces. An interesting asymptotically flat solution arises for Λ =0.

Extended open inflationary universes

In this paper we study a type of one-field model for open inflationary universe models in the context of the Jordan-Brans-Dicke theory. In the scenario of a one-bubble universe model we determine and characterize the existence of the Coleman-De Lucia instanton, together with the period of inflation after tunnelling has occurred. Our results are analogous to those found in the Einstein General Relativity models.

LETTER: BTZ Black Hole from (3+1) Gravity

We propose an approach for constructing spatial slices of (3+1) spacetimes with cosmological constant but without a matter content, which yields (2+1) vacuum with Λ solutions. The reduction mechanism from (3+1) to (2+1) gravity is supported on a criterion in which the Weyl tensor components are required to vanish together with a dimensional reduction via an appropriate foliation. By using an adequate reduction mechanism from the Plebański–Carter[A] solution in (3+1) gravity, the (2+1) BTZ solution can be obtained.

Curvature of the universe and the dark energy potential

The flatness of an accelerating universe model (characterized by a dark energy scalar field

Closed universe and the first Doppler peak of the cosmic microwave background spectrum

ensuremath{chi})

Viscous cosmologies in scalar tensor theories for Kasner type metrics

is mimicked from a curved model that is filled with, apart from the cold dark matter component, a quintessencelike scalar field Q. In this process, we characterize the original scalar potential

A critical-density closed Universe in Brans-Dicke Theory

V(Q)

H{z) diagnostics to discriminate dark energy models

and the mimicked scalar potential

Quantum cosmology for hyperextended inflation

V(ensuremath{chi})