Inflationary Tensor Perturbations After BICEP

Abstract

The measurement of B-mode polarization of the cosmic microwave background at large angular scales by the BICEP experiment suggests a stochastic gravitational wave background from early-universe inflation with a surprisingly large amplitude. The power spectrum of these tensor perturbations can be probed both with further measurements of the microwave background polarization at smaller scales, and also directly via interferometry in space. We show that sufficiently sensitive high-resolution B-mode measurements will ultimately have the ability to test the inflationary consistency relation between the amplitude and spectrum of the tensor perturbations, confirming their inflationary origin. Additionally, a precise B-mode measurement of the tensor spectrum will predict the tensor amplitude on solar system scales to 20% accuracy for an exact power law tensor spectrum, so a direct detection will then measure the running of the tensor spectral index to high precision.

5 pages, 1 figure version 3 has been accepted for publication in PRL, typos corrected, and references added

References in corpus (4)

• CMBPol Mission Concept Study: Probing Inflation with CMB Polarization
• The Spectrum of Gravitational Radiation from Primordial Turbulence
• Prospects for direct detection of primordial gravitational waves
• WMAP-normalized Inflationary Model Predictions and the Search for Primordial Gravitational Waves with Direct Detection Experiments

Cited by in corpus (11)

• Generalised tensor fluctuations and inflation
• ${\varphi }^2$ or Not ${\varphi }^2$: Testing the Simplest Inflationary Potential
• Compatibility of Planck and BICEP2 in the Light of Inflation
• Multi-wavelength constraints on the inflationary consistency relation
• Gravitational wave consistency relations for multifield inflation
• How much can we learn about the physics of inflation?
• Classicalization of inflationary perturbations by collapse models in the light of BICEP2
• Studying Inflation with Future Space-Based Gravitational Wave Detectors
• The History of Inflation from Microwave Background Polarimetry and Laser Interferometry
• The Tilt of Primordial Gravitational Waves Spectra from BICEP2
• Constraints on the cosmological parameters from BICEP2, Planck and WMAP