Perturbations in warm inflation

Oliveira, H. P. de; Jorás, S. E.

doi:10.1103/physrevd.64.063513

Cited by 79 publications

(96 citation statements)

References 21 publications

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“…Therefore, warm inflation [12,13] (non-isentropic), as a * mmotaharfar2000@gmail.com † erfan.massaeli@gmail.com ‡ hr-sepangi@sbu.ac.ir complementary scenario, has been constructed to avoid such problems by introducing a supplementary viscose term having a dissipation coefficient which illustrates the rate of energy exchange between inflaton and radiation field. In fact, inflaton concurrently dissipates into radiation whereby primeval radiation will not heavily be diluted during inflation and smoothly enters the radiation era, for details see [14][15][16][17][18][19][20][21][22][23][24]. As a result, warm inflation not only inherits the features of conventional inflation but also removes disparities coming from the reheating phase and thus alleviates the initial condition [25], cures the overlarge amplitude of the inflaton field and circumvents the so-called eta-problem [26].…”

Section: Introductionmentioning

confidence: 99%

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

2017

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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.

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Section: Introductionmentioning

confidence: 99%

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

2017

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“…and the energy momentum flux (ρ + p)v. A complete set of perturbation equations can be obtained from the Einstein field equations and the scalar field equation [29,30]. From the Einstein equation we obtaiṅ…”

Section: Cosmological Perturbationsmentioning

confidence: 99%

“…This technique should be good for order of magnitude estimates. For more accurate treatment of the density perturbations it is nessesary to use the cosmological perturbation equations, which can be found in the literature [28,29,30].…”

Section: Introductionmentioning

confidence: 99%

Scalar perturbation spectra from warm inflation

2004

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We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a combination of thermal field theory and thermodynamics. The perturbation equations include the effects of a damping coefficient Γ and a thermodynamic potential V . We give an analytic expression for the spectral index of scalar fluctuations in terms of a new slow-roll parameter constructed from Γ. A series of toy models, inspired by spontaneous symmetry breaking and a known form of the damping coefficient, lead to a spectrum with ns > 1 on large scales and ns < 1 on small scales.

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“…More accurate treatments of density perturbations have followed [30,32,33,34,35], which use the cosmological perturbation equations. Following our recent results [39], working in the zero-shear gauge with perturbed metric…”

Section: Observational Testsmentioning

confidence: 99%

“…In [29] an order of magnitude estimate of density perturbations during warm inflation was computed by matching the thermally produced fluctuations to gauge invariant parameters when the fluctuations cross the horizon (for other phenomenological treatments of warm inflation see [30,31,32,33,34,35]). This work provided a clear statement of the consistency condition.…”

Section: Observational Testsmentioning

confidence: 99%

Warm inflation solution to the eta problem

Berera¹

2003

Proceedings of International Workshop on Astroparticle and High Energy Physics — PoS(AHEP2003)

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Warm inflationary dynamics is shown to satisfy both the slow-roll and density perturbation constraints for m φ H or equivalently η 1 and for inflaton field amplitudes much below the Planck scale, φ < m pl . I start by reviewing the two types of inflation dynamics, isentropic or cold inflation and nonisentropic or warm inflation.In the former, inflation occurs without radiation production, whereas in the latter both radiation production and inflation occur concurrently. I then discuss recent, detailed, quantum field theory calculations showing that many generic inflation models, including hybrid inflation, which were believed only to have cold inflation regimes, in fact have regimes of both warm and cold inflation. These results dispel many foregone assumptions generally made up to now about inflation models and bring to the fore various elementary issues that must be addressed to do reliable calculations from inflation models. I also discuss density perturbations and observational consequences of warm inflation, especially related to WMAP. Finally I show that warm inflation has intrinsic features that make the "eta problem" nonexistent, and field amplitudes are below the Planck scale.

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Perturbations in warm inflation

Cited by 79 publications

References 21 publications

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

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

Scalar perturbation spectra from warm inflation

Warm inflation solution to the eta problem

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