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Register a new userAn update on single field models of inflation in light of WMAP7
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In this paper we summarise the status of single field models of inflation in light of the WMAP 7 data release. We find little has changed since the 5 year release, and results are consistent with previous findings. The increase in the upper bound on the running of the spectral index impacts on the status of the production of Primordial Black Holes from single field models. The lower bound on the equilateral configuration of the non-gaussianity parameter is reduced and thus the bounds on the theoretical parameters of (UV) DBI single brane models are weakened. In the case of multiple coincident branes the bounds are also weakened and the two, three or four brane cases will produce a tensor-signal that could possibly be observed in the future.
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We are interested on studing various inflationary spectrum perturbation parameters in the context of the Randall-Sandrum type 2 Braneworld model. We consider in particular three types of potentials. We apply the slow-roll approximation in the high energy limit to constraint the parameter potentials by confronting our results to recent WMAP7 observations. We show that, for some values of the e-folding number N; the monomial potential provides the best fit results to observations data.
Using the latest release from WMAP, I find that for a reasonable number of e-folds the tree-level potential with self coupling power p=3 is now excluded from the 2-sigma region, the axion monodromy model with the power alpha=2/3 is now excluded from the 1-sigma confidence region for N=47 e-folds and for N=61. alpha=2/5 is also excluded from the 2-sigma region for N=61. I also find that since the upper bound on the running has been reduced, a significant abundance of PBHs requires fractional powers of self-coupling in the Hilltop-type model.
We review 51 models of single-field inflation, paying special attention to the possibility that self-resonance of the unstable inflaton perturbations leads to reheating. We compute Floquet exponents for the models that are consistent with current cosmological data. We find five models that exhibit a strong instability, but only in one of them -- KKLT inflation -- the equation of state efficiently approaches that of radiation.
Combining cosmic microwave background (CMB) data from Planck satellite data, Baryon Acoustic Oscillations (BAO) measurements and Type Ia supernovae (SNe Ia) data, we obtain the bounds on total neutrino masses $M_ u$ with the approximation of degenerate neutrino masses and for three dark energy models: the cosmological constant ($Lambda$CDM) model, a phenomenological emergent dark energy (PEDE) model and a model-independent quintessential parameterization (HBK). The bounds on the sum of neutrino masses $M_ u$ depend on the dark energy (DE) models. In the HBK model, we confirm the conclusion from some previous work that the quintessence prior of dark energy tends to tighten the cosmological constraint on $M_ u$. On the other hand, the PEDE model leads to larger $M_ u$ and a nonzero lower bound. Besides, we also explore the correlation between three different neutrino hierarchies and dark energy models.
We present two cases where the addition of the $R^2$ term to an inflationary model leads to single-field inflation instead of two-field inflation as is usually the case. In both cases we find that the effect of the $R^2$ term is to reduce the value of the tensor-to-scalar ratio $r$.
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