Quadratic, Higgs and hilltop potentials in the Palatini gravity

Bostan, Nilay

doi:10.48550/arxiv.1908.09674

Cited by 3 publications

(3 citation statements)

References 49 publications

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“…These couplings are different in the two approaches. This has been first pointed out in [13] and has attracted the interest of many authors since, , with still continuing activity, [43][44][45][46][47][48][49].…”

Section: Introductionmentioning

confidence: 89%

Reheating in R2 Palatini inflationary models

Gialamas

Lahanas

2020

Phys. Rev. D

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We consider R 2 inflation in the Palatini gravity assuming the existence of scalar fields, coupled to gravity in the most general manner. These theories, in the Einstein frame, and for one scalar field h, share common features with K -inflation models. We apply this formalism for the study of popular inflationary models, whose potentials are monomials, V ∼ h n , with n a positive even integer. We also study the Higgs model non-minimally coupled to gravity. Although these have been recently studied, in the framework of the Palatini approach, we show that the scalar power spectrum severely constrains these models. Although we do not propose a particular reheating mechanism, we show that the quadratic ∼ h 2 and the Higgs model can survive these constraints with a maximum reheating temperature as large as ∼ 10 15 GeV , when reheating is instantaneous. However, this can be only attained at the cost of a delicate fine-tuning of couplings. Deviations from this fine-tuned values can still yield predictions compatible with the cosmological data, for couplings that lie in very tight range, giving lower reheating temperatures.

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Section: Introductionmentioning

confidence: 89%

Reheating in R2 Palatini inflationary models

Gialamas

Lahanas

2020

Phys. Rev. D

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“…[93] for a recent review on metric Higgs inflation and Refs. [14,22,30,32,36,39,42,43,46,47,53] for recent studies on Palatini-Higgs inflation.…”

Section: Higgs Inflationmentioning

confidence: 99%

Tracing the high energy theory of gravity: an introduction to Palatini inflation

Tenkanen

2020

Gen Relativ Gravit

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We present an introduction to cosmic inflation in the context of Palatini gravity, which is an interesting alternative to the usual metric theory of gravity. In the latter case only the metric g µν determines the geometry of space-time, whereas in the former case both the metric and the space-time connection Γ λ µν are a priori independent variables -a choice which can lead to a theory of gravity different from the metric one. In scenarios where the field(s) responsible for cosmic inflation are coupled non-minimally to gravity or the gravitational sector is otherwise extended, assumptions of the underlying gravitational degrees of freedom can have a big impact on the observational consequences of inflation. We demonstrate this explicitly by reviewing several interesting and well-motivated scenarios including Higgs inflation, R 2 inflation, and ξ-attractor models. We also discuss some prospects for future research and argue why r = 10 −3 is a particularly important goal for future missions that search for signatures of primordial gravitational waves.

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“…One may also consider other inflationary models based on monomial potentials with the inflaton field coupled non-minimally to the scalar curvature, e.g., see[21,35] for the quadratic inflation model with a non-minimal coupling to gravity.5 See[76][77][78] for the studies of chaotic inflation with a non-minimal coupling to gravity.…”

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confidence: 99%

Quintessential Inflation in Palatini Gravity

Verner

2020

Preprint

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We study a model of quintessential inflation in the context of Palatini gravity. As a representative example, we consider the Peebles-Vilenkin model of quintessential inflation with a small non-minimal coupling to gravity, which is consistent with the most recent Planck measurements.At the end of inflation, the inflaton field passes through a tachyonic region and it leads to explosive particle production through the tachyonic preheating process. After preheating, the Universe becomes dominated by the kinetic energy of the inflaton and enters a period of kination. Eventually, the total energy density of the Universe becomes dominated by radiation, resulting in reheating.We find that the model predicts the reheating temperature values T RH ∼ O(10 3 −10 8 ) GeV, which is significantly above the temperature of Big Bang Nucleosynthesis. Following reheating, the inflaton field rolls down the quintessence potential until it freezes. Since the quintessence remains frozen until the present day, the residual potential energy density at this field value explains the observed dark energy density.

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Quadratic, Higgs and hilltop potentials in the Palatini gravity

Cited by 3 publications

References 49 publications

Reheating in R2 Palatini inflationary models

Reheating in R2 Palatini inflationary models

Tracing the high energy theory of gravity: an introduction to Palatini inflation

Quintessential Inflation in Palatini Gravity

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