Reconstruction of the primordial power spectra with Planck and BICEP2

Abstract

By using the cubic spline interpolation method, we reconstruct the shape of the primordial scalar and tensor power spectra from the recently released {\it Planck} temperature and BICEP2 polarization cosmic microwave background data. We find that the vanishing scalar index running ($\dd n_s/\dd\ln k$) model is strongly disfavored at more than $3\sigma$ confidence level on the $k=0.0002$ Mpc${}^{-1}$ scale. Furthermore, the power-law parameterization gives a blue-tilt tensor spectrum, no matter using only the first 5 bandpowers $n_t=1.20_{-0.64}^{+0.56}(95$ or the full 9 bandpowers $n_t=1.24_{-0.58}^{+0.51}(95$ of BICEP2 data sets. Unlike the large tensor-to-scalar ratio value ($r\sim 0.20$) under the scale-invariant tensor spectrum assumption, our interpolation approach gives $r_{0.002}<0.060(95$ by using the first 5 bandpowers of BICEP2 data. After comparing the results with/without BICEP2 data, we find that {\it Planck} temperature with small tensor amplitude signals and BICEP2 polarization data with large tensor amplitude signals dominate the tensor spectrum reconstruction on the large and small scales, respectively. Hence, the resulting blue tensor tilt actually reflects the tension between {\it Planck} and BICEP2 data.

complementary results without BICEP2 added, references add, typos corrected, 10 figures, 5 tables, 11 pages

References in corpus (6)

• Starting the Universe: Stable Violation of the Null Energy Condition and Non-standard Cosmologies
• G-inflation: inflation driven by the Galileon field
• New Ekpyrotic Cosmology
• Model selection applied to reconstruction of the Primordial Power Spectrum
• Suppressing the impact of a high tensor-to-scalar ratio on the temperature anisotropies
• Compensation for large tensor modes with iso-curvature perturbations in CMB anisotropies

Cited by in corpus (19)

• Inflationary universe from perfect fluid and $F(R)$ gravity and its comparison with observational data
• Blue Tensor Spectrum from Particle Production during Inflation
• Blue-tilted Tensor Spectrum and Thermal History of the Universe
• Wiggly Whipped Inflation
• Just enough inflation: power spectrum modifications at large scales
• Generation of large-scale magnetic fields, non-Gaussianity, and primordial gravitational waves in inflationary cosmology
• Joint Planck and WMAP Assessment of Low CMB Multipoles
• Pre-inflationary genesis with CMB B-mode polarization
• Light Sterile Neutrinos and Inflationary Freedom
• Negative running prevents eternal inflation
• Large Scale Suppression of Scalar Power on a Spatial Condensation
• Searching for local features in primordial power spectrum using genetic algorithms
• The Tilt of Primordial Gravitational Waves Spectra from BICEP2
• Revisiting scalar and tensor perturbations in a nonlocal gravity
• BICEP's acceleration
• Knot reconstruction of the scalar primordial power spectrum with Planck, ACT, and SPT CMB data
• Spectral Distortion Signatures of Step-like Inflationary Potential
• Updated reduced CMB data and constraints on cosmological parameters
• Inflationary Dynamics Reconstruction via Inverse-Scattering Theory