Abstract
We study the polynomial chaotic inflation model with a single scalar field in a double well quartic potential which has recently been shown to be consistent with Planck data. In particular, we study the effects of lifting the degeneracy between the two vacua on the inflationary observables, i.e., spectral index ns and tensor-to-scalar perturbation ratio rT. We find that removing the degeneracy allows the model to satisfy the upper limit constraints on rT from Planck data, provided the field starts near the local maximum. We also calculate the scalar power spectrum and non-Gaussianity parameter fNL for the primordial scalar perturbations in this model.
Highlights
Inflation is regarded as the standard cosmological paradigm to describe the physics of the very early Universe
As long as there is such a local maximum, the initial value of the inflaton field should be below the local maximum since otherwise the inflaton would be trapped in the false vacuum
In this Letter, we have explored in detail the (B, φi) space within the slow-roll regime for the quartic potential
Summary
It leads to a causal mechanism to generate almost scale invariant fluctuations on cosmological scales, with small deviations that follow from the precise microphysics of inflation. This prediction is consistent with the recently announced measurements of the cosmic microwave background (CMB) anisotropies by the Planck satellite. The latest data allow us to constrain the inflationary model besides giving a slightly red tilted spectral index ns = 0.9603 ± 0.0073, ruling out exact scale invariance ns = 1 at over 5σ [1]. The data reinforced the ruling out of single-field inflationary models V (φ) = φn with n ≥ 2, which were already disfavored or marginally disfavored by WMAP.
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