Gravitational Waves and Scalar Perturbations from Spectator Fields

Abstract

The most conventional mechanism for gravitational waves (gw) production during inflation is the amplification of vacuum metric fluctuations. In this case the gw production can be uniquely related to the inflationary expansion rate $H$. For example, a gw detection close to the present experimental limit (tensor-to-scalar ratio $r\sim 0.1$) would indicate an inflationary expansion rate close to $10^{14}\mathrm{GeV}$. This conclusion, however, would be invalid if the observed gw originated from a different source. We construct and study one of the possible covariant formulations of the mechanism suggested in [43], where a spectator field $\sigma$ with a sound speed $c_s\ll 1$ acts as a source for gw during inflation. In our formulation $\sigma$ is described by a so-called $P(X)$ Lagrangian and a non-minimal coupling to gravity. This field interacts only gravitationally with the inflaton, which has a standard action. We compute the amount of scalar and tensor density fluctuations produced by $\sigma$ and find that, in our realization, $r$ is not enhanced with respect to the standard result but it is strongly sensitive to $c_s$, thus breaking the direct $r\leftrightarrow H$ connection.

arXiv comment22 pages

References in corpus (76)

• Particle Physics Models of Inflation and the Cosmological Density Perturbation
• k-Inflation
• BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales
• Generalized G-inflation: Inflation with the most general second-order field equations
• Perturbations in k-inflation
• From k-essence to generalised Galileons
• Planck 2013 results. XXII. Constraints on inflation
• DBI in the Sky
• Signature of Gravity Waves in Polarization of the Microwave Background
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Gravitational Radiation from First-Order Phase Transitions
• A Probe of Primordial Gravity Waves and Vorticity
• What would we learn by detecting a gravitational wave signal in the cosmic microwave background anisotropy?
• Warm Inflation
• Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
• The cosmological gravitational wave background from primordial density perturbations
• Planck 2013 Results. XXIV. Constraints on primordial non-Gaussianity
• Relativistic second-order perturbations of the Einstein-de Sitter Universe
• Large Nongaussianity in Axion Inflation
• Naturally inflating on steep potentials through electromagnetic dissipation
• Particle production during inflation and gravitational waves detectable by ground-based interferometers
• CMBPol Mission Concept Study: Probing Inflation with CMB Polarization
• A Measurement of the Cosmic Microwave Background B-Mode Polarization Power Spectrum at Sub-Degree Scales with POLARBEAR
• Toward an Understanding of Foreground Emission in the BICEP2 Region
• CMB polarization from secondary vector and tensor modes
• General Relativistic Dynamics of Irrotational Dust: Cosmological Implications
• Parity violation in the Cosmic Microwave Background from a pseudoscalar inflaton
• Galileon inflation
• Cosmology with Nonminimal Derivative Couplings
• Phenomenology of a Pseudo-Scalar Inflaton: Naturally Large Nongaussianity
• BICEP2 II: Experiment and Three-Year Data Set
• The Gelaton Scenario: Equilateral non-Gaussianity from multi-field dynamics
• Warm inflation model building
• Gravity waves and non-Gaussian features from particle production in a sector gravitationally coupled to the inflaton
• The Inflationary Trispectrum for Models with Large Non-Gaussianities
• Mass hierarchies and non-decoupling in multi-scalar field dynamics
• Resilience of the standard predictions for primordial tensor modes
• Trapped Inflation
• Inflation and the Theory of Cosmological Perturbations
• UV-Protected Inflation
• Blue Tensor Spectrum from Particle Production during Inflation
• Non-gaussianity from the trispectrum in general single field inflation
• New Sources of Gravitational Waves during Inflation
• An inflationary model with small scalar and large tensor nongaussianities
• Non-Bunch-Davies Initial State Reconciles Chaotic Models with BICEP and Planck
• Enhancing Inflationary Tensor Modes through Spectator Fields
• Reconciliation of High Energy Scale Models of Inflation with Planck
• Large non-Gaussianities in the Effective Field Theory Approach to Single-Field Inflation: the Bispectrum
• Short Distance Physics and the Consistency Relation for Scalar and Tensor Fluctuations in the Inflationary Universe
• Parity violation in the CMB bispectrum by a rolling pseudoscalar
• Large non-Gaussianities in the Effective Field Theory Approach to Single-Field Inflation: the Trispectrum
• Universal Constraints on Axions from Inflation
• A Nearly Scale Invariant Spectrum of Gravitational Radiation from Global Phase Transitions
• Running of the Spectral Index and Violation of the Consistency Relation Between Tensor and Scalar Spectra from trans-Planckian Physics
• Did BICEP2 see vector modes? First B-mode constraints on cosmic defects
• B-modes and the Nature of Inflation
• Can topological defects mimic the BICEP2 B-mode signal?
• Can primordial magnetic fields be the origin of the BICEP2 data?
• BICEP2 implications for single-field slow-roll inflation revisited
• Transient cosmic acceleration from interacting fluids
• Remarks about the Tensor Mode Detection by the BICEP2 Collaboration and the Super-Planckian Excursions of the Inflaton Field
• Breaking discrete symmetries in the effective field theory of inflation
• How Well Can We Really Determine the Scale of Inflation?
• The Maximal Amount of Gravitational Waves in the Curvaton Scenario
• Rapid field excursions and the inflationary tensor spectrum
• Gravitational waves from a curvaton model with blue spectrum
• Can Self-Ordering Scalar Fields explain the BICEP2 B-mode signal?
• Probing the Gravitational Wave Signature from Cosmic Phase Transitions at Different Scales
• Gravitational waves from first order phase transitions during inflation
• On the Trispectrum of Galileon Inflation
• Do Mixed States save Effective Field Theory from BICEP?
• Tensors, BICEP2, prior dependence, and dust
• Bogoliubov Excited States and the Lyth Bound
• Killing the Straw Man: Does BICEP Prove Inflation at the GUT Scale?
• The Trispectrum in the Effective Theory of Inflation with Galilean symmetry
• Trispectrum from Co-dimension 2(n) Galileons

Cited by in corpus (40)

• Cosmological Backgrounds of Gravitational Waves
• Gravitational Waves Induced by non-Gaussian Scalar Perturbations
• Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves
• Universal infrared scaling of gravitational wave background spectra
• Imprints of Primordial Non-Gaussianity on Gravitational Wave Spectrum
• Scale-dependent gravitational waves from a rolling axion
• Primordial Gravitational Waves from Axion-Gauge Fields Dynamics
• The Gravitational-Wave Physics
• Rolling axions during inflation: perturbativity and signatures
• Pulsar Timing Array Constraints on the Induced Gravitational Waves
• Primordial black holes and stochastic gravitational wave background from inflation with a noncanonical spectator field
• Primordial gravitational waves in supersolid inflation
• Probing non-Gaussian Stochastic Gravitational Wave Backgrounds with LISA
• Primordial Black Hole Formation in Non-Minimal Curvaton Scenario
• Non-Gaussianity from Axion-Gauge Fields Interactions during Inflation
• Primordial Tensor Perturbation in Double Inflationary Scenario with a Break
• Squeezed tensor non-Gaussianity in non-attractor inflation
• A new mechanism to enhance primordial tensor fluctuations in single field inflation
• On Synthetic Gravitational Waves from Multi-field Inflation
• Tensor non-Gaussianities from Non-minimal Coupling to the Inflaton
• Primordial Gravitational Waves with LISA
• Interferometer Constraints on the Inflationary Field Content
• Unveiling the nonlinear dynamics of a rolling axion during inflation
• Bound on Induced Gravitational Waves during Inflation Era
• On chromonatural inflation in string theory
• Primordial perturbations from dilaton-induced gauge fields
• Primordial non-Gaussianities of gravitational waves beyond Horndeski
• Is Trans-Planckian Censorship a Swampland Conjecture?
• Boosting GWs in Supersolid Inflation
• Generation of gravitational waves from symmetry restoration during inflation
• Primordial gravitational wave phenomenology with polarized Sunyaev Zel'dovich tomography
• Gravitational waves induced by spinor fields
• Loop corrections to primordial fluctuations from inflationary phase transitions
• Traces of a Heavy Field in Gravitational Waves
• D-Flation
• Gravitational Wave From Axion-like Particle Inflation
• Synthetic Gravitational Waves from a Rolling Axion Monodromy
• Vector field instability and the primordial tensor spectrum
• A narrow-band parameterization for the stochastic gravitational wave background
• Revisiting the Chern-Simons interaction during inflation with a non-canonical pseudo-scalar