Chaotic inflation in modified gravitational theories

Felice, Antonio De; Tsujikawa, Shinji; Elliston, Joseph; Tavakol, Reza

doi:10.1088/1475-7516/2011/08/021

Cited by 62 publications

(91 citation statements)

References 115 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, B should be positive since it later appears under a radical in power spectrum (72) and δ GX should also be positive in order to avoid instability and ghosts [45,46], therefore, κ X and A are positive quantities. Consequently, to have det(M ) > 0 and Tr(M ) < 0, one arrives at the condition on c as |c| ≤ 4 − 2b,…”

Section: Stability Analysismentioning

confidence: 99%

Power spectra in warm G inflation and its consistency: Stochastic approach

2017

View full text Add to dashboard Cite

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 slowroll 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 P SR parameters and Galileon flow functions. Finally, the model is solved for chaotic self-interacting potentials, particularly the renormalizable Higgs potential λ 4 φ 4 , and shown to be consistent with observations in the weak dissipation Q 1 + 3and G-dominant 3 δ GX δ X 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.

show abstract

Section: Stability Analysismentioning

confidence: 99%

Power spectra in warm G inflation and its consistency: Stochastic approach

2017

View full text Add to dashboard Cite

show abstract

“…[18]. The interesting feature of Galileons to allow self-accelerating de Sitter solutions while providing a ghost-free theory [16,19] has generated a flurry of investigations, targeted at cosmological models and their observational signatures [20][21][22][23][24][25][26][27][28], inflationary JHEP07(2013)067 models [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45], gravitational lensing [46], spherically symmetric solutions in the vicinity of compact sources [47], Binary Pulsars [48][49][50], etc. .…”

Section: Jhep07(2013)067mentioning

confidence: 99%

Superluminality in the Bi- and Multi-Galileon

Fromont

Rham

Heisenberg

et al. 2013

J. High Energ. Phys.

View full text Add to dashboard Cite

We re-explore the Bi-and Multi-Galileon models with trivial asymptotic conditions at infinity and show that propagation of superluminal fluctuations is a common and unavoidable feature of these theories, unlike previously claimed in the literature. We show that all Multi-Galileon theories containing a Cubic Galileon term exhibit superluminalities at large distances from a point source, and that even if the Cubic Galileon is not present one can always find sensible matter distributions in which there are superluminal modes at large distances. In the Bi-Galileon case we explicitly show that there are always superluminal modes around a point source even if the Cubic Galileon is not present. Finally, we briefly comment on the possibility of avoiding superluminalities by modifying the asymptotic conditions at infinity.

show abstract

“…In fact, the leading-order power spectra of tensor and scalar perturbations were derived for inflationary models in the framework of Horndeski theories [12,13]. These results were employed to place observational constraints on individual models (such as slow-roll inflation [3], k-inflation [14], Starobinsky inflation [1], Higgs inflation [15,16]) from the WMAP and Planck data [17,18].…”

Section: Introductionmentioning

confidence: 99%

Inflationary gravitational waves in the effective field theory of modified gravity

Felice

Tsujikawa

2015

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

In the approach of the effective field theory of modified gravity, we derive the second-order action and the equation of motion for tensor perturbations on the flat isotropic cosmological background. This analysis accommodates a wide range of gravitational theories including Horndeski theories, its generalization, and the theories with spatial derivatives higher than second order (e.g., Hořava-Lifshitz gravity). We obtain the inflationary power spectrum of tensor modes by taking into account corrections induced by higher-order spatial derivatives and slow-roll corrections to the de Sitter background. We also show that the leading-order spectrum in concrete modified gravitational theories can be mapped on to that in General Relativity under a disformal transformation. Our general formula will be useful to constrain inflationary models from the future precise measurement of the B-mode polarization in the cosmic microwave background.

show abstract

Chaotic inflation in modified gravitational theories

Cited by 62 publications

References 115 publications

Power spectra in warm G inflation and its consistency: Stochastic approach

Power spectra in warm G inflation and its consistency: Stochastic approach

Superluminality in the Bi- and Multi-Galileon

Inflationary gravitational waves in the effective field theory of modified gravity

Contact Info

Product

Resources

About