From Jose Pedro Mimoso

Research: Research

My research work is mainly devoted to cosmology.

Cosmology aims at answering questions such as:

  • What is the geometry of the universe?
  • How does it evolve (How fast does it expand? How old is it?) ?
  • What is the composition of the Universe?
  • How did the structures that exist in the universe form?
  • What seeded the formation of galaxies and the large-scale structure?

In the last two decades Cosmology has witnessed a significant observational revolution. Instruments such as the Hubble Space Telescope,the VLTI, the COBE and, subsequently, the WMAP and Planck satellites, the Boomerang and Maxima balloons, several other space missions, and also the cooperative efforts of large research consortiae responsible for various surveys as important as the SSDS2 and 2CdF red-shift surveys, and in particular the Supernovae follow up program, have hugely improved the quantity and quality of data that is available.

On large scales, these cosmological observations led one to conclude that our understanding of the origin and e volution of the Universe based on the theory of General Relativity (GR) requires that most of the energy content of the Universe is in the form of currently unknown dark matter and dark energy components that may permeate much, if not all space-time. Indeed, recent Cosmic Microwave background Radiation (CMB) data indicate that our Universe is well described, within the framework of GR, by a nearly flat Robertson-Walker metric.Moreover, combination of CMB, supernovae, baryon acoustic oscillations and large scale structure data are consistent with each other only if, in the cosmic budget of energy, dark energy corresponds to about 70% of the critical density, while dark matter to about 25% and baryonic matter to only about 5%.

Moreover, the presence of the dark energy component is related to an unexpected acceleration of the universe close to our epoch. This is a demanding issue both because we do not have an explanation for nature of this new dark component, which is repulsive, nor do we know the reason why it only produces effect on the expansion of the universe after galaxies and other structures have formed. Therefore addressing these latter questions is of pressing importance at present.

In this framework, the subjects of my research work are:

  • Study of cosmological models based on generalised gravity theories (scalar-tensor theories, higher-order gravity theories,...);
  • Inflation and the dynamics of cosmological models with scalar fields, namely the analysis of the mechanisms of thermal recovery after inflation ('preheating' e 'warm inflation');
  • Cosmological models with multi-components with interactions and couplings.
  • Dynamics of anisotropic/higher dimensional cosmological models (role of anisotropic stresses, classification of the dynamics, isotropization);
  • Study of gravitational collapse, and of the issue of the immunity of local physics to the cosmological expansion;
  • Models with negative curvature and the large-scale structure of the universe.
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