195 citations · 323 across the 19 of their papers we have counts for
19 papers
Singularities in inflationary cosmological models
L. Fernández-Jambrina
Due to the accelerated expansion of the universe, the possibility of formation of singularities has changed from the classical Big Bang and Big Crunch singularities to include a nu…
Comment on "From geodesics of the multipole solutions to the perturbed Kepler problem"
L. Fernández-Jambrina
In this comment we explain the discrepancies mentioned by the authors between their results and ours about the influence of the gravitational quadrupole moment in the perturbative…
-cosmological singularities
L. Fernández-Jambrina
In this paper we characterize barotropic index singularities of homogeneous isotropic cosmological models. They are shown to appear in cosmologies for which the scale factor is ana…
Absence of singularities in a cosmological perfect fluid solution
F. J. Chinea, L. Fernández-Jambrina, J. M. M. Senovilla
In this lecture we will show some properties of a singularity-free solution to Einstein's equations and its accordance with some theorems dealing with singularities. We will also d…
Surface densities in General Relativity
F. J. Chinea, L. Fernández-Jambrina
In this lecture we deal with the construction of surface densities for the angular momentum of the sources of asymptotically flat vacuum stationary axisymmetric spacetimes. These s…
Non-regular Potentials and Sources for Static Axisymmetric Electrovacs
L. Fernández-Jambrina
In this lecture a new formalism for constructing electromagnetic surface sources for static axisymmetric electrovacs is presented. The electrostatic and magnetostatic sources are d…
Magnetic Moment Density from Lack of Smoothness of the Ernst Potential
L. Fernández-Jambrina
In this talk it is shown a way for constructing magnetic surface sources for stationary axisymmetric electrovac spacetimes possessing a non-smooth electromagnetic Ernst potential.…
Non-singular inhomogeneous stiff fluid cosmology
L. Fernández-Jambrina
In this talk we show a stiff fluid solution of the Einstein equations for a cylindrically symmetric spacetime. The main features of this metric are that it is non-separable in como…
On non-singular inhomogeneous cosmological models
L. Fernández-Jambrina, L. M. González-Romero
In this talk we would like to review recent results on non-singular cosmological models. It has been recently shown that among stiff perfect fluid inhomogeneous spacetimes the abse…
Geodesic completeness of diagonal metrics
L. Fernández-Jambrina
In this talk a sufficient condition for a diagonal orthogonally transitive cylindrical metric to be geodesically complete is given. The condition is weak enough to comprise a…
Singularity-free orthogonally-transitive cylindrical spacetimes
L. Fernández-Jambrina
In this talk a previous theorem on geodesic completeness of diagonal cylindrical spacetimes will be generalized to cope with the nondiagonal case. A sufficient condition for such s…
Towards an open set of regular cosmological models
L. Fernández-Jambrina, L. M. González-Romero
The possibility of obtaining an open set of regular cosmological models is discussed. Cylindrical stiff perfect fluid cosmologies are studied in detail. The condition for geodesic…
Geodesically complete cylindrical spacetimes
L. Fernández-Jambrina
A sufficient condition for an orthogonally transitive G2 cylindrical spacetime to be singularity-free is shown. The condition is general enough to comprise all known geodesically c…
New families of singularity-free cosmological models
L. Fernández-Jambrina, L. M. González-Romero
In this talk we extend a family of geodesically complete stiff fluid cosmological models to the case in which the velocity of the fluid is not orthogonal to the gradient of…
Non-singular Stiff Fluids
L. Fernández-Jambrina, L. M. González-Romero
In this talk the possibility of constructing geodesically complete inhomogeneous stiff fluid cosmologies is discussed. A family with infinite parameters is derived. A wide and easy…
Geodesic Completeness around Sudden Singularities
L. Fernández-Jambrina, R. Lazkoz
In this talk we analyze the effect of recently proposed classes of sudden future singularities on causal geodesics of FLRW spacetimes. Geodesics are shown to be extendible and just…
Past singularities in phantom theories
L. Fernández-Jambrina
FLRW models filled with just dark energy are shown to have a finite past, since causal geodesics cannot be extended beyond a certain proper time. It is shown that curvature measure…
Singular fate of the universe in modified theories of gravity
L. Fernández-Jambrina, Ruth Lazkoz
In this paper we study the final fate of the universe in modified theories of gravity. As compared with general relativistic formulations, in these scenarios the Friedmann equation…
Geodesic behavior of sudden future singularities
L. Fernández-Jambrina, Ruth Lazkoz
In this paper we analyze the effect of recently proposed classes of sudden future singularities on causal geodesics of FLRW spacetimes. Geodesics are shown to be extendible and jus…