Scale-invariant perturbations from NEC violation: A new variant of Galilean Genesis
arXiv:1611.01906 · doi:10.1103/PhysRevD.95.064001
Abstract
We propose a novel branch of the Galilean Genesis scenario as an alternative to inflation, in which the universe starts expanding from Minkowski in the asymptotic past with a gross violation of the null energy condition (NEC). This variant, described by several functions and parameters within the Horndeski scalar-tensor theory, shares the same background dynamics with the existing Genesis models, but the nature of primordial quantum fluctuations is quite distinct. In some cases, tensor perturbations grow on superhorizon scales. The tensor power spectrum can be red, blue, or scale invariant, depending on the model, while scalar perturbations are nearly scale invariant. This is in sharp contrast to typical NEC-violating cosmologies, in which a blue tensor tilt is generated. Though the primordial tensor and scalar spectra are both nearly scale invariant as in the inflationary scenario, the consistency relation in our variant of Galilean Genesis is non-standard.
arXiv comment10 pages, 4 figures; v2: published version
References in corpus (44)
- Generalized G-inflation: Inflation with the most general second-order field equations
- From k-essence to generalised Galileons
- Imperfect Dark Energy from Kinetic Gravity Braiding
- G-inflation: inflation driven by the Galileon field
- The Emergent Universe: inflationary cosmology with no singularity
- Towards a Nonsingular Bouncing Cosmology
- On the Generation of a Scale-Invariant Spectrum of Adiabatic Fluctuations in Cosmological Models with a Contracting Phase
- Horizon crossing and inflation with large η
- Duality Invariance of Cosmological Perturbation Spectra
- A Critical Review of Classical Bouncing Cosmologies
- Galilean Genesis: an alternative to inflation
- The Emergent Universe: An Explicit Construction
- G-Bounce
- The Null Energy Condition and its violation
- String Gas Cosmology
- Bouncing Galileon Cosmologies
- Generic instabilities of non-singular cosmologies in Horndeski theory: a no-go theorem
- Cosmological perturbations through a simple bounce
- The Effective Field Theory of nonsingular cosmology
- Resilience of the standard predictions for primordial tensor modes
- Alternatives to Cosmological Inflation
- Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis
- Towards Anisotropy-Free and Non-Singular Bounce Cosmology with Scale-invariant Perturbations
- Anisotropy in a Nonsingular Bounce
- Curvature perturbation at the local extremum of the inflaton's potential
- Stability of Geodesically Complete Cosmologies
- Subluminal Galilean Genesis
- Singularities in Inflationary Cosmology: A Review
- A Galileon Design of Slow Expansion
- DBI Realizations of the Pseudo-Conformal Universe and Galilean Genesis Scenarios
- Cosmological disformal invariance
- DBI Genesis: An Improved Violation of the Null Energy Condition
- Emergent Universe Scenario via Quintom Matter
- Galilean Creation of the Inflationary Universe
- Inflation from Minkowski Space
- Galileon bounce after ekpyrotic contraction
- Generalized Galilean Genesis
- Cosmology of the Spinor Emergent Universe and Scale-invariant Perturbations
- Gravitational Waves in Bouncing Cosmologies from Gauge Field Production
- Adiabatic Spectra During Slowly Evolving
- The slow expansion with nonminimal derivative coupling and its conformal dual
- Primordial Gravitational Waves Induced by Magnetic Fields in an Ekpyrotic Scenario
- Pre-inflationary genesis with CMB B-mode polarization
- Reheating and Primordial Gravitational Waves in Generalized Galilean Genesis
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- Horndeski theory and beyond: a review
- The Effective Field Theory of nonsingular cosmology: II
- Intermittent null energy condition violations during inflation and primordial gravitational waves
- Broken blue-tilted inflationary gravitational waves: a joint analysis of NANOGrav 15-year and BICEP/Keck 2018 data
- Pulsar timing array observations as possible hints for nonsingular cosmology
- Genesis with general relativity asymptotics in beyond Horndeski theory
- Cosmological consequences of a principle of finite amplitudes
- Toward evading the strong coupling problem in Horndeski genesis
- Nanohertz gravitational waves from NEC violation in the early universe
- Improved DHOST Genesis
- Generating enhanced primordial GWs during inflation with intermittent violation of NEC and diminishment of GW propagating speed
- Perturbative unitarity and NEC violation in genesis cosmology
- Primordial non-Gaussianity from Galilean Genesis without strong coupling problem
- Horndeski Genesis: strong coupling and absence thereof