B-modes and the sound speed of primordial fluctuations
arXiv:1412.0033 · doi:10.1103/PhysRevD.91.063525
Abstract
It was recently shown that a large value of the tensor to scalar ratio implies a constraint on the minimum value of the sound speed of primordial curvature perturbations during inflation that is stronger than current bounds coming from non-Gaussianity measurements. Here we consider additional aspects related to the measurement of B-modes that may provide additional leverage to constrain the sound speed parametrizing non-canonical models of inflation. We find that a confirmation of the consistency relation between the tensor to scalar ratio and the tensor spectral index is not enough to rule out non-canonical models of inflation with a sound speed different from unity. To determine whether inflation was canonical or not, one requires knowledge of additional parameters, such as the running of the spectral index of scalar perturbations . We also study how other parameters related to the ultra violet completion of inflation modify the dependence of on . For instance, we find that heavy degrees of freedom interacting with curvature fluctuations generically tend to make the constraint on the sound speed stronger. Our results, combined with future observations of primordial B-modes, may help to constrain the background evolution of non-canonical models of inflation.
arXiv comment11 pages, 7 figures, v2 version accepted in PRD
References in corpus (64)
- Non-Gaussian features of primordial fluctuations in single field inflationary models
- k-Inflation
- BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales
- Towards Inflation in String Theory
- The Effective Field Theory of Inflation
- Planck 2013 results. XXII. Constraints on inflation
- DBI in the Sky
- A Joint Analysis of BICEP2/Keck Array and Planck Data
- Observational Signatures and Non-Gaussianities of General Single Field Inflation
- Quantum Contributions to Cosmological Correlations
- Monodromy in the CMB: Gravity Waves and String Inflation
- Gravity Waves and Linear Inflation from Axion Monodromy
- What would we learn by detecting a gravitational wave signal in the cosmic microwave background anisotropy?
- Scalar Speed Limits and Cosmology: Acceleration from D-cceleration
- A more accurate analytic calculation of the spectrum of cosmological perturbations produced during inflation
- Ghost Inflation
- Planck 2013 Results. XXIV. Constraints on primordial non-Gaussianity
- Non-Gaussianities in Single Field Inflation and their Optimal Limits from the WMAP 5-year Data
- Features of heavy physics in the CMB power spectrum
- Signatures of Supersymmetry from the Early Universe
- CMBPol Mission Concept Study: Probing Inflation with CMB Polarization
- Toward an Understanding of Foreground Emission in the BICEP2 Region
- Kahler Moduli Inflation
- General inflaton potentials in supergravity
- The Effective Field Theory of Multifield Inflation
- Equilateral Non-Gaussianity and New Physics on the Horizon
- The Gelaton Scenario: Equilateral non-Gaussianity from multi-field dynamics
- Inflation Physics from the Cosmic Microwave Background and Large Scale Structure
- Effective theories of single field inflation when heavy fields matter
- CLASS: The Cosmology Large Angular Scale Surveyor
- de Sitter vacua in no-scale supergravities and Calabi-Yau string models
- A joint analysis of Planck and BICEP2 B modes including dust polarization uncertainty
- On the importance of heavy fields during inflation
- Heavy fields, reduced speeds of sound and decoupling during inflation
- Strongly Coupled Perturbations in Two-Field Inflationary Models
- Inflation in Realistic D-Brane Models
- On Slow-roll Moduli Inflation in Massive IIA Supergravity with Metric Fluxes
- Effective Field Theory and Decoupling in Multi-field Inflation: An Illustrative Case Study
- Constraints on modular inflation in supergravity and string theory
- Non-Bunch-Davies Initial State Reconciles Chaotic Models with BICEP and Planck
- The POLARBEAR Experiment
- Inflating in a Trough: Single-Field Effective Theory from Multiple-Field Curved Valleys
- Effective field theory of weakly coupled inflationary models
- A Field Range Bound for General Single-Field Inflation
- B-modes and the Nature of Inflation
- Compatibility of Planck and BICEP2 in the Light of Inflation
- Decoupling Survives Inflation: A Critical Look at Effective Field Theory Violations During Inflation
- The Knotted Sky II: Does BICEP2 require a nontrivial primordial power spectrum?
- Oscillatory features in the curvature power spectrum after a sudden turn of the inflationary trajectory
- Kahler potentials for Planck inflation
- Is Higgs Inflation Dead?
- Cosmic inflation in a landscape of heavy-fields
- On quantifying and resolving the BICEP2/Planck tension over gravitational waves
- Cosmological constraints on general, single field inflation
- Tensors, non-Gaussianities, and the future of potential reconstruction
- Statistical diagnostics to identify Galactic foregrounds in B-mode maps
- A geometric bound on F-term inflation
- The everpresent eta-problem: knowledge of all hidden sectors required
- On degenerate models of cosmic inflation
- The Atacama B-Mode Search: CMB Polarimetry with Transition-Edge-Sensor Bolometers
- Negative running prevents eternal inflation
- Effects of the speed of sound at large-N
- Non-Gaussianity after BICEP2
- On UltraViolet effects in protected inflationary models