320 research outputs found
Recent progress in Affleck-Dine baryogenesis
In the MSSM, cosmological scalar field condensates formed along flat
directions of the scalar potential (Affleck-Dine condensates) are typically
unstable with respect to formation of Q-balls, a type of non-topological
soliton. I discuss the creation and growth of the quantum seed fluctuations
which catalyse the collapse of the condensate. In D-term inflation models, the
fluctuations of squark fields in the flat directions also give rise to
isocurvature density fluctuations stored in the Affleck-Dine condensate. After
the condensate breaks up, these can be perturbations in the baryon number, or,
in the case where the present neutralino density comes directly from B-ball
decay, perturbations in the number of dark matter neutralinos. The latter case
results in a large enhancement of the isocurvature perturbation, which should
be observable by PLANCK.Comment: 8 pages, 2 figures; invited talk at COSMO9
Mixed Inflaton and Spectator Field Models after Planck
We investigate the possibility that the primordial perturbation has two
sources: the inflaton and a spectator field, which is not dynamically important
during inflation but which after inflation can contribute to the curvature
perturbation. The recent Planck results on the power spectrum and
non-Gaussianity allow us to put constraints on such mixed models. In the
generic case, where no specific model for the inflaton or the spectator is
assumed, one finds that in the mixed scenario it is possible to have a large
trispectrum with tau_NL >> (f_NL)^2. The constraints on inflation models in the
plane of the spectral index and tensor-to-scalar ratio are modified by the
presence of a spectator and depend also on the ratio of the
spectator-to-inflaton power R. If one chooses the spectator to be the curvaton
with a quadratic potential, non-Gaussianities can be computed and imply
restrictions on possible values of R. We also consider a mixed curvaton and
chaotic inflation model and show that even quartic chaotic inflation is still
feasible in the context of mixed models.Comment: 14 pages, 4 figure
The Dynamics of Affleck-Dine Condensate Collapse
In the MSSM, cosmological scalar field condensates formed along flat
directions of the scalar potential (Affleck-Dine condensates) are typically
unstable with respect to formation of Q-balls, a type of non-topological
soliton. We consider the dynamical evolution of the Affleck-Dine condensate in
the MSSM. We discuss the creation and linear growth, in F- and D-term inflation
models, of the quantum seed perturbations which in the non-linear regime
catalyse the collapse of the condensate to non-topological soliton lumps. We
study numerically the evolution of the collapsing condensate lumps and show
that the solitons initially formed are not in general Q-balls, but Q-axitons, a
pseudo-breather which can have very different properties from Q-balls of the
same charge. We calculate the energy and charge radiated from a spherically
symmetric condensate lump as it evolves into a Q-axiton. We also discuss the
implications for baryogenesis and dark matter.Comment: 21 pages LaTeX, 11 figure
Constraining Isocurvature Fluctuations with the Planck Surveyor
We consider the detection possibilities of isocurvature fluctuations in the
future CMB satellite experiments MAP and Planck for different cosmological
reference models. We present a simultaneous 10 parameter fit (8 for the case of
open model) to determine the correlations between the cosmological parameters,
including isocurvature cold dark matter contribution to the anisotropy.
Assuming that polarization information can be fully exploited, we find that an
isocurvature perturbation can be detected by the Planck Surveyor if the ratio
of the initial isocurvature and adiabatic perturbation amplitude is larger than
0.07. In the absence of polarization data, the signal from isocurvature
perturbations can be confused with tensor perturbations or early reionization
effects, and the limit is larger by almost an order of magnitude.Comment: 6 pages, 4 figures, revte
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