The attractive behaviour of ultra-slow-roll inflation

Pattison, Chris; Vennin, Vincent; Assadullahi, Hooshyar; Wands, David

doi:10.1088/1475-7516/2018/08/048

Cited by 70 publications

(70 citation statements)

References 40 publications

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“…There has been much work done recently on inflation models with a quasi-inflection point in the potential near the end of inflation. Such a feature introduces a USR period where the inflaton slows down and the necessary amplification of the curvature power spectrum takes place [18,19]. The scales which exit the horizon during this time later re-enter shortly after the end of inflation, whereby the radiation plasma inherits the high curvature perturbation as an increase in the overdensity.…”

Section: Introductionmentioning

confidence: 99%

Primordial black hole formation in inflationary α -attractor models

Mahbub

2020

Phys. Rev. D

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The formation of primordial black holes is studied using superconformal inflationary α-attractors. An inflaton potential is constructed with a plateau-like region which brings about the onset of an ultra slow-roll region where the required enhancement in the curvature power spectrum takes place. This is accomplished by carefully finetuning the parameters in the potential. For the parameter sets, the amount of observable inflation is such that the curvature perturbation P R peaks at ∼ 10 14 Mpc −1 , producing PBHs in the mass window 10 16 g ≤ M ≤ 10 18 g. The reheating period after inflation is taken into account to determine whether or not PBH formation takes place in such a phase. Finally, the spectrum of second order gravitational waves, that can arise due to the curvature perturbation enhancement, is calculated.

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Section: Introductionmentioning

confidence: 99%

Primordial black hole formation in inflationary α -attractor models

Mahbub

2020

Phys. Rev. D

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“…Our approach complements the techniques developed in Refs. [16][17][18][19][20][21][22][23][24][25][26][27][28] to study attractor behavior for inflationary models, either by specifying a particular form for the scalar field's potential, V (φ), or by adopting the Hamilton-Jacobi formalism to study the evolution of the Hubble parameter as a function of the scalar field, H(φ).…”

Section: Introductionmentioning

confidence: 99%

Flows into inflation: An effective field theory approach

Azhar

Kaiser

2018

Phys. Rev. D

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We analyze the flow into inflation for generic "single-clock" systems, by combining an effective field theory approach with a dynamical-systems analysis. In this approach, we construct an expansion for the potential-like term in the effective action as a function of time, rather than specifying a particular functional dependence on a scalar field. We may then identify fixed points in the effective phase space for such systems, order by order, as various constraints are placed on the Mth time derivative of the potential-like function. For relatively simple systems, we find significant probability for the background spacetime to flow into an inflationary state and for inflation to persist for at least 60 e-folds. Moreover, for systems that are compatible with single-scalar-field realizations, we find a single, universal functional form for the effective potential, VðϕÞ, which is similar to the well-studied potential for power-law inflation. We discuss the compatibility of such dynamical systems with observational constraints.

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“…By varying the Kähler curvature, we can derive the α attractor with n s = 1 − 2/N and r = 12α/N 2 [33], and the α attractor can also be derived from general scalar-tensor theory of gravity [29]. The constant-roll inflation with the slow-roll parameter η H being a constant [34,35] breaks the slow-roll condition if η H is not small and has richer physics than slow-roll inflation because it includes both slow-roll and ultra slow-roll cases [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. Furthermore, the ultra slow-roll inflation can generate large density perturbation to seed the formation of primordial black holes [55][56][57][58].…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of extended inflationary potentials for attractors

Gao

Gong

2018

Eur. Phys. J. Plus

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We give the procedure to reconstruct the extended inflationary potentials for attractors and use the α attractor and the constant-roll model as examples to show how to reconstruct the class of extended inflationary potentials in the strong coupling limit. We also derive the strong coupling condition which the coupling constant ξ satisfies. The class of extended inflationary potentials has the same attractor, and the reconstructed extended inflationary potentials are consistent with the observational constraints. The existence of the attractors from extended inflationary models further challenges the model discrimination just by the observables n s and r.

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The attractive behaviour of ultra-slow-roll inflation

Cited by 70 publications

References 40 publications

Primordial black hole formation in inflationary α -attractor models

Primordial black hole formation in inflationary α -attractor models

Flows into inflation: An effective field theory approach

Reconstruction of extended inflationary potentials for attractors

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