How much primordial tensor mode is allowed?

Abstract

The presence of a significant amount of gravitational radiation in the early Universe affects the total energy density and hence the expansion rate in the early epoch. In this work, we develop a physical model to connect the parameter of relativistic degree of freedom $N_{\mathrm{eff}}$ with the amplitude and shape of primordial tensor power spectrum, and use the CMB temperature and polarization data from {\it Planck} and BICEP2/KECK Array, and the primordial deuterium measurement from damped Lyman-$\alpha$ (DLA) systems to constrain this model. We find that with this extra relation $\Delta N_{\mathrm{eff}}(r,n_{\mathrm{t}})$, the tensor-to-scalar ratio $r$ is constrained to be $r<0.07$ ($3\sigma$ C.L.) and the tilt of tensor power spectrum is $n_{\mathrm{t}}=-0.01\pm 0.31$ ($1\sigma$ C.L.) for {\it Planck}+BICEP2+KECK+[D/H] data. This achieves a much tighter constraint on the tensor spectrum and provides a stringent test for cosmic inflation models. In addition, the current constraint on $N_{\mathrm{eff}}=3.122\pm 0.171$ excludes the possibility of fourth neutrino species at more than $5\sigma$ C.L.

12 pages, 7 figures

References in corpus (54)

• Planck 2015 results. XIII. Cosmological parameters
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• Cosmological parameters from CMB and other data: a Monte-Carlo approach
• Planck 2018 results. I. Overview and the cosmological legacy of Planck
• The Simons Observatory: Science goals and forecasts
• Gravitational Wave Experiments and Early Universe Cosmology
• A Joint Analysis of BICEP2/Keck Array and Planck Data
• Planck 2015 results. XI. CMB power spectra, likelihoods, and robustness of parameters
• One percent determination of the primordial deuterium abundance
• A Measurement of the Damping Tail of the Cosmic Microwave Background Power Spectrum with the South Pole Telescope
• BICEP2 / Keck Array x: Constraints on Primordial Gravitational Waves using Planck, WMAP, and New BICEP2/Keck Observations through the 2015 Season
• Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves
• The effects of He I 10830 on helium abundance determinations
• Ekpyrotic and Cyclic Cosmology
• Limits on the Stochastic Gravitational Wave Background from the North American Nanohertz Observatory for Gravitational Waves
• Precision measures of the primordial abundance of deuterium
• Upper Limits on the Stochastic Gravitational-Wave Background from Advanced LIGO's First Observing Run
• How Massless Neutrinos Affect the Cosmic Microwave Background Damping Tail
• Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure
• PArthENoPE: Public Algorithm Evaluating the Nucleosynthesis of Primordial Elements
• A Realistic Determination of the Error on the Primordial Helium Abundance: Steps Toward Non-Parametric Nebular Helium Abundances
• The metal-poor end of the Spite plateau. 1: Stellar parameters, metallicities and lithium abundances
• Direct detection of the inflationary gravitational wave background
• The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters
• Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: implications for the early universe
• Cosmic Microwave Background Fluctuations from Gravitational Waves: An Analytic Approach
• Tensor Modes from a Primordial Hagedorn Phase of String Cosmology
• A First Detection of the Acoustic Oscillation Phase Shift Expected from the Cosmic Neutrino Background
• The cosmic gravitational wave background in a cyclic universe
• New constraints on primordial gravitational waves from Planck 2015
• The primordial helium abundance from updated emissivities
• The primordial deuterium abundance of the most metal-poor damped Lyman-alpha system
• COrE (Cosmic Origins Explorer) A White Paper
• Blue-tilted Tensor Spectrum and Thermal History of the Universe
• Spikes in the Relic Graviton Background from Quintessential Inflation
• Constraining The Early-Universe Baryon Density And Expansion Rate
• Searching for Light Relics with Large-Scale Structure
• Implication of the proton-deuteron radiative capture for Big Bang Nucleosynthesis
• Observing the Inflaton Potential
• Constraints on Cosmological Parameters from the 500 deg${}^2$ SPTpol Lensing Power Spectrum
• Constraints of relic gravitational waves by Pulsar Timing Array: Forecasts for the FAST and SKA projects
• Phases of New Physics in the BAO Spectrum
• Inflation with violation of the null energy condition
• Updated Constraints and Forecasts on Primordial Tensor Modes
• SPIDER: CMB polarimetry from the edge of space
• Multi-wavelength constraints on the inflationary consistency relation
• Cosmological Parameters from pre-Planck CMB Measurements: a 2017 Update
• Observational Constraints on Theories with a Blue Spectrum of Tensor Modes
• Neutrino constraints: what large-scale structure and CMB data are telling us?
• SPIDER: A Balloon-borne Large-scale CMB Polarimeter
• Constraints on Cosmological Parameters from the Angular Power Spectrum of a Combined 2500 deg${}^2$ SPT-SZ and Planck Gravitational Lensing Map
• Constraints on standard and non-standard early Universe models from CMB B-mode polarization
• Comparison of results on $N_{\mathrm{eff}}$ from various Planck likelihoods

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• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Inflationary interpretation of the stochastic gravitational wave background signal detected by pulsar timing array experiments
• Inflation, the Hubble Tension and Early Dark Energy: an alternative overview
• Towards a reliable calculation of relic radiation from primordial gravitational waves
• Inflationary Potential as seen from Different Angles: Model Compatibility from Multiple CMB Missions
• Implications for primordial black holes from cosmological constraints on scalar-induced gravitational wave
• Tracking the Multifield Dynamics with Cosmological Data: A Monte Carlo approach
• Constraining Holographic Dark Energy and Analyzing Cosmological Tensions
• Enhancement of small-scale induced gravitational waves from the soliton/oscillon domination
• Impact of particle production during inflation on the CMB detection