Effect of transitions in the Planck mass during inflation on primordial power spectra

Abstract

We study the effect of sudden transitions in the effective Planck mass during inflation on primordial power spectra. Specifically, we consider models in which this variation results from the non-minimal coupling of a Brans-Dicke type scalar field. We find that the scalar power spectra develop features at the scales corresponding to those leaving the horizon during the transition. In addition, we observe that the tensor perturbations are largely unaffected, so long as the variation of the Planck mass is below the percent level. Otherwise, the tensor power spectra exhibit damped oscillations over the same scales. Due to significant features in the scalar power spectra, the tensor-to-scalar ratio r shows variation over the corresponding scales. Thus, by studying the spectra of both scalar and tensor perturbations, one can constrain sudden but small variations of the Planck mass during inflation. We illustrate these effects with a number of benchmark single- and two-field models. In addition, we comment on their implications and the possibility to alleviate the tension between the observations of the tensor-to-scalar ratio performed by the Planck and BICEP2 experiments.

23 pages, 13 figures; to match version accepted for publication in Phys. Rev. D

References in corpus (22)

• Monodromy in the CMB: Gravity Waves and String Inflation
• Toward an Understanding of Foreground Emission in the BICEP2 Region
• The Powers of Monodromy
• A joint analysis of Planck and BICEP2 B modes including dust polarization uncertainty
• D7-Brane Chaotic Inflation
• New Universal Local Feature in the Inflationary Perturbation Spectrum
• Blue Tensor Spectrum from Particle Production during Inflation
• Evolving Newton's Constant, Extended Gravity Theories and SnIa Data Analysis
• Energy Transfer in Multi Field Inflation and Cosmological Perturbations
• Fingerprints of Galactic Loop I on the Cosmic Microwave Background
• On Features and Nongaussianity from Inflationary Particle Production
• BICEP2 implications for single-field slow-roll inflation revisited
• Constraining a possible time-variation of the gravitational constant through "gravitochemical heating" of neutron stars
• Suppressing the impact of a high tensor-to-scalar ratio on the temperature anisotropies
• Primordial Perturbations from Multifield Inflation with Nonminimal Couplings
• Do Newton's G and Milgrom's a_0 vary with cosmological epoch ?
• Testing quantum gravity effects with latest CMB observations
• Constraining a possible time variation of the gravitational constant G with terrestrial nuclear laboratory data
• The WiggleZ Dark Energy Survey: constraining the evolution of Newton's constant using the growth rate of structure
• Isocurvature perturbations and tensor mode in light of Planck and BICEP2
• Jump in fluid properties of inflationary universe to reconcile scalar and tensor spectra
• Constraints on scalar-tensor theories of gravity from observations

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• An exploration of an early gravity transition in light of cosmological tensions
• Large Scale Suppression of Scalar Power on a Spatial Condensation
• Understanding large scale CMB anomalies with the generalized non-minimal derivative coupling during inflation
• Non-standard hierarchies of the runnings of the spectral index in inflation
• Stabilising the Planck mass shortly after inflation