Download PROYECTO FONDECYT N° 1020578

PROYECTO FONDECYT 1051086
TITULO:
POSSIBLE MATTER SOURCES OF THE UNIVERSE.
Investigador Principal
Mauricio Cataldo Monsalves
Facultad/Depto.
Ciencias/Física
E-Mail
[email protected]
Coinvestigadores
Sergio del Campo A. (P.U.C.V.)
Patricio Salgado A. (U. de C.)
OBJETIVOS:
- The general goal is to study a wide range of cosmological models for the Universe,
which might describe either early or the present stage of the Universe during its
expansion. The possibility of an anisotropic state at early times in the evolution of the
Universe is a very natural idea to explore. These anisotropies could have many possible
sources.
RESUMEN Y RESULTADOS:
In this proposal we want to study a wide range of cosmological models for the Universe,
which might describe either early or the present stage of the Universe during its expansion.
One of the key problems of the current cosmology is deciding which kind of matter sources
are present in the Universe. This means that there is a notable uncertainty about the
presence or absence of matter fields, which might contribute to the total energy density
today. At the early stage the kind of matter fields is even more uncertain.
One of main points of this research is to investigate the consequences of the existence of an
inflationary era for the evolution of the early Universe, taking into account dissipative
processes described by a viscous cosmic fluid. The early expansion stage may be described
by isotropic or anisotropic line elements (for instance, such as Friedmann-RobertsonWalker or Kasner type metrics respectively). Imperfect cosmic fluid is a suitable source for
anisotropic Universe models. In this case the matter content may be a viscous (or
nonviscous) fluid, a magnetic and an electric field (liner or nonlinear electrodynamics),
scalar fields, long wavelength gravitational waves, Yang-Mills fields, axion fields in low
energy string theory and different kind of topological defects, such that cosmic strings,
domain walls, among others.
The present expansion stage of the Universe is accelerating. On the one hand this
acceleration has been associated with the presence of a cosmological constant, but on the
other hand this acceleration may be explained by the so called “quintessence” models.
With respect to the present scenarios we shall consider cosmological models described
byisotropic or anisotropic metrics, with perfect or imperfect fluids together with a
quintessence-type scalar field. A possible relation between the homogeneity of the
Universe and the dimensionality of space will also be treated.
All considered models for the early Universe must give the necessary initial conditions for
the formation of the large scale structure observed in the Universe today. On the other
hand, the cosmological models must be compatible with the strong energy condition and
with the second law of the thermodynamics, so that a generation of entropy in viscous
models could be appropriately described.
Perturbations around a background solution allow us to determine explicit expressions for
the contrast energy-density /, together with the power spectrum P(K) with inflationary
initial conditions. These expressions will be confronted with related astronomical
observations (such that the observational data obtained by recently completed
BOOMERANG and MAXIMA experiments and by the second generation satellite
experiments such that WMAO and PLANCK), so that the specific parameters that enter in
our models could be determined.