Power spectra in warm G-inflation and its consistency: stochastic approach

Abstract

Recently, it has been realized that the so-called G-inflation model inspired by supplementing a generalized covariant Galileon-like non-linear derivative self-interacting term to the standard kinetic term should be ruled out from inflationary models. This is due to the fact that it suffers from lack of an oscillatory phase at the end of the inflationary regime which is typically accompanied by the appearance of a negative squared propagation speed of the scalar mode leading to instabilities of small-scale perturbations. In this regard, the warm G-inflation scenario is proposed where for G-inflation to survive, the Galileon scalar field is coupled to the radiation field through a dissipation term which results in removing the reheating period due to the characteristics of warm inflationary scenario. In so doing, a linear stability analysis is first performed to obtain the appropriate slow-roll conditions in such a proposal. Cosmological perturbations of the model are then investigated by utilizing fluctuation-dissipation theorem and analytical expressions are derived for observable quantities; the power spectrum, tilt spectral index and tensor-to-scalar ratio in terms of $PSR$ parameters and Galileon flow functions. Finally, the model is solved for chaotic self-interacting potentials, particularly the renormalizable Higgs potential $\frac{\lambda }{4}{\varphi }^4$, and shown to be consistent with observations in the weak dissipation $Q\ll 1+3\frac{{\delta }_{GX}}{{\delta }_X}$ and G-dominant $3\frac{{\delta }_{GX}}{{\delta }_X}\gg 1$ regime despite its large self-coupling, since the energy scale at the horizon crossing is depressed by the synergy of Galileon and thermal effects.

arXiv comment13 pages, 4 figures, to appear in PRD

References in corpus (44)

• Planck 2015 results. XIII. Cosmological parameters
• Towards the Theory of Reheating After Inflation
• k-Inflation
• Reheating after Inflation
• Perturbations in k-inflation
• Covariant Galileon
• DBI in the Sky
• Warm Inflation
• Generalized Galileons: All scalar models whose curved background extensions maintain second-order field equations and stress tensors
• Formalising the Slow-Roll Approximation in Inflation
• Ghost Inflation
• G-inflation: inflation driven by the Galileon field
• Inflation scenario via the Standard Model Higgs boson and LHC
• New Model of Inflation with Non-minimal Derivative Coupling of Standard Model Higgs Boson to Gravity
• Thermally Induced Density Perturbations in the Inflation Era
• Warm Inflation and its Microphysical Basis
• Galileon Cosmology
• Scalar perturbation spectra from warm inflation
• Conditions for the cosmological viability of the most general scalar-tensor theories and their applications to extended Galileon dark energy models
• Self-Accelerating Universe in Galileon Cosmology
• Warm Little Inflaton
• Perturbation Spectra in the Warm Inflationary Scenario
• The importance of being warm (during inflation)
• Is Warm Inflation Possible?
• Higgs G-inflation
• Density fluctuations from warm inflation
• Non-gaussianity in fluctuations from warm inflation
• On the consistency of warm inflation
• Cosmological Perturbations in the New Higgs Inflation
• Cosmological fluctuations of a random field and radiation fluid
• Inflation with TeV-scale gravity
• Warm Inflation with a General Form of the Dissipative Coefficient
• On Perturbations in Warm Inflation
• Spontaneous baryogenesis in warm inflation
• Potential-driven Galileon inflation
• Chaotic inflation in modified gravitational theories
• Observational Constraints on Monomial Warm Inflation
• Density perturbations in warm inflation and COBE normalization
• Inflationary Initial Conditions Consistent with Causality
• Extension of warm inflation to noncanonical scalar fields
• Graceful exit from Higgs G-inflation
• Non-gaussianity in the strong regime of warm inflation
• Warming up for Planck
• G-Warm inflation

Cited by in corpus (15)

• Warm inflation as a way out of the swampland
• Recent developments in warm inflation
• Warm brane inflation with an exponential potential: A consistent realization away from the swampland
• The warm inflation story
• Reconstructing warm inflation
• Irreversible thermodynamical description of warm inflationary cosmological models
• Power-counting during single-field slow-roll inflation
• Galileon intermediate inflation
• Warm Higgs G-inflation: predictions and constraints from Planck 2015 likelihood
• Warm inflation with non-comoving scalar field and radiation fluid
• Primordial Black Holes Dark Matter and Secondary Gravitational Waves from Warm Higgs-G Inflation
• Trans-Planckian Effects in Warm Inflation
• G-Warm inflation: Intermediate model
• On the role of dissipative effects in the quantum gravitational onset of warm Starobinsky inflation in a closed universe
• Revisiting Barrow's Graduated Inflationary Universe: A Warm perspective