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EDUARDO Guendelman
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A transition between bouncing hyper-inflation to ΛCDM from diffusive scalar fields
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We consider the history of the universe from
the big bang to the late period in the context
of a
unified interacting dark energy - dark matter
model. The model is based on the Two Measures
Theories,
which introduces metric independent volume
elements and this allows to construct unified
Dark
Matter Dark Energy, where the cosmological
constant appears as an integration constant
associated
to the equation of motion of the measure
fields. The Dynamical space time Theories
generalize
the Two Measure Theories by introducing a
vector field, whose equation of motion guarantees
the
conservation of a source of a certain Energy
Momentum tensor, which may be related, but
in general
is not the same as the gravitational Energy
Momentum tensor. By considering the dynamical
space
field appearing in another part of the action
or by demanding that the dynamical space
time vector
be a gradient of a scalar, we obtain a diffusive
non conservation of an energy momentum tensor.
These generalizations leads at the end to
a formulation of interacting DE-DM dust models
in the
form of a diffusive type interacting Unified
Dark Energy and Dark Matter scenario. A numerical
solution of the theories shows that in some
cases the evolution of the very early universe
is governed
by Stiff equation of state, and undergoes
to ΛCDM. In other cases the universe
bounces to hyper
inflation. But all of these solutions have
another final transition to ΛCDM as
a fixed point for
the late universe
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