One of the most difficult questions which the comunity of physicists and astronomers
have to answer concerns the compatibility between the ideal
Friedmann-Lemaitre-Robertson-Walker model (with an isotropic and
homogeneous spatial section) with astronomical observations which reveal the
existence of different scales of inhomogeneity in the Universe. Some models for the
formation of structure - galaxies, clusters of galaxies - require the ocurrence of small
perturbations in a primordial phase in the Universe, where the geometry of spacetime
is controlled either by radiation or by exotic matter. It happens, e.g., inthe so called
inflationary models. In such models, small initial quantum perturbations are amplified
due to gravitational instabilities, generating the observed structures in the Universe.
These small perturbations would be determined - in a variety of models - by
high-energy quantum physical interactions. In this way, it is established a deep
connection between Quantum Field Theory and High Energy Physics with
gravitational theory. In the last two decades, extra galactic astronomical data have
been obtained with much more precision. As a consequence, the analysis of the
production of these structures from initial perturbations has obtained a large impulse.
Hence, high-energy phenomena and the theories that describe them could be
investigated in a new scenario, the cosmological one, with much more scientific rigor.