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The
theme of the school is the formation of large scale structures
after the results of the Planck mission. The aim of this school is,
after an overview of the standard model containing the inflationary
paradigm, to focus on alternatives. The model of inflation, although
generally confirmed at phenomenological level with these new data,
suffers from conceptual difficulties when we want to use it in the
framework of a "realistic" theory ( great unification theory string ,
for example) . Indeed, as models at large field ( Large Field
Inflation) are now virtually eliminated , one has to consider models
for which the potential of the inflaton contains a plateau (Small Field
Inflation) or several fields (Hybrid Inflation). And in the latter
case, one must understand the reason why the non-local gaussianity are
so weak . Moreover, the "recent" history of the Universe , since the
nucleosynthesis to the formation of structures , requires, so that the
observations are consistent with the theory to introduce two
ingredients not yet well understood (Dark Matter and Dark Energy).
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Context and Scientific Objectives
The
standard model of cosmology can be considered as a very effective
phenomenological approach to account for observations, but it requires
a clarification to the fundamental level. Consider alternatives and
their consequences is a way to approach this understanding. This will
lead either to reaffirm the current paradigm on more solid theoretical
foundations, or to introduce a new one.
In practice, the selected axis is not only to
study the different
alternatives to very primordial level , but also these alternatives
that suggest a different interpretation of the observations . For
example, the cosmological constant needed to reproduce the data appears
just when large scale structures become nonlinear. Hence, this
coincidence might be due to the presence of inhomogeneities
producing a back reaction that we would interpret wrongly as an
acceleration of the expansion. Alternatively, one might envisage that
the law of gravity dependent on scale or energy in order to interpret
these observations.
The topics that are covered in this school
are:
- Standard Model: phenomenological description
of the data (e.g., dark matter and dark energy ) , inflation models and
slow-roll parameters.
- Thorough
discussion of the currently available data, including the most recent (
those that will be available shortly before school) , including
anomalies detected in Planck data, and the forthcoming proposals, such
as those based on 21cm or the BAO).
- Alternatives to inflation models ( Bouncing ,
String Gas Cosmology, ... ) and their predictions on present and future
data.
- Numerical simulations of the formation of
structures with emphasis on
the question of how these simulations depend on the standard model and
how it would be possible to operate in different contexts.
- Inhomogeneous
models of the universe and spatial averaging methods in Cosmology, or
how to account for non-linear effects in general relativity on the mean
evolution of the universe.
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