115 research outputs found
Angular Power Spectrum in Modular Invariant Inflation Model
We propose a scalar potential of inflation, motivated by modular invariant
supergravity, and compute the angular power spectra of the adiabatic density
perturbations that result from this model. The potential consists of three
scalar fields, S, Y and T, together with two free parameters. By fitting the
parameters to cosmological data at the fixed point T=1, we find that the
potential behaves like the single-field potential of S, which slowly rolls down
along the minimized trajectory in Y. We further show that the inflation
predictions corresponding to this potential provide a good fit to the recent
three-year WMAP data, e.g. the spectral index n_s = 0.951. The TT and TE
angular power spectra obtained from our model almost completely coincide with
the corresponding results obtained from the \LambdaCDM model. We conclude that
our model is considered to be an adequate theory of inflation that explains the
present data, although the theoretical basis of this model should be further
explicated.Comment: 8 pages, 8 figures and 1 tabl
Effect of the length of inflation on angular TT and TE power spectra in power-law inflation
The effect of the length of inflation on the power spectra of scalar and
tensor perturbations is estimated using the power-law inflation model with a
scale factor of a(t) = t^q. Considering various pre-inflation models with
radiation-dominated or scalar matter-dominated periods before inflation in
combination with two matching conditions, the temperature angular power
spectrum (TT) and temperature-polarization cross-power spectrum (TE) are
calculated and a likelihood analysis is performed. It is shown that the
discrepancies between the Wilkinson Microwave Anisotropy Probe (WMAP) data and
the LCDM model, such as suppression of the spectrum at l = 2,3 and oscillatory
behavior, may be explained by the finite length of inflation model if the
length of inflation is near 60 e-folds and q > 300. The proposed models retain
similar values of chi^2 to that achieved by the LCDM model with respect to fit
to the WMAP data, but display different characteristics of the angular TE power
spectra at l < 20.Comment: 41 pages, 11 figure
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