Inflation model building with an accurate measure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>e</mml:mi></mml:mrow></mml:math>-folding

Chongchitnan, Sirichai

doi:10.1103/physrevd.94.043526

Cited by 4 publications

(16 citation statements)

References 16 publications

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“…which is simply the power-law potential. This proof strengthens the result in [11] in which we showed that the predictions in the n s -r plane for the Gaussian H (φ) coincide what those of the power-law potentials.…”

Section: The Generalised Gaussian Modelsupporting

confidence: 90%

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Primordial Gravitational Waves and Reheating in a New Class of Plateau-Like Inflationary Potentials

Chongchitnan

2018

Universe

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Abstract:We study a new class of inflation model parametrized by the Hubble radius, such that aH ∝ exp(−αφ) n . These potentials are plateau-like, and reduce to the power-law potentials in the simplest case n = 2. We investigate the range of model parameters that is consistent with current observational constraints on the scalar spectral index and the tensor-to-scalar ratio. The amplitude of primordial gravitational waves in these models is shown to be accessible by future laser interferometers such as DECIGO. We also demonstrate how these observables are affected by the temperature and equation of state during reheating. We find that a large subset of this model can support instantaneous reheating, as well as very low reheating temperatures of order a few MeV, giving rise to interesting consequences for dark-matter production.

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Section: The Generalised Gaussian Modelsupporting

confidence: 90%

“…Whilst H (φ) must be a deceasing function, H(φ) can either be decreasing or increasing 1 . The two approaches are quite different, but complementary 2 (see [11,17] for further dynamical comparisons).…”

Section: The H (φ) Parametrizationmentioning

confidence: 99%

Primordial Gravitational Waves and Reheating in a New Class of Plateau-Like Inflationary Potentials

Chongchitnan

2018

Universe

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“…In [8], we presented an alternative framework for inflation model building in which the physical number of e-folds, Ñ , is the key temporal parameter (as opposed to the approximation N ). We summarise the main results below.…”

Section: A New Framework Of Inflation Model Buildingmentioning

confidence: 99%

“…In this work, we present an extension of the construction in [8] and demonstrate that the discrepancy in the predicted GW amplitude, by assuming that N = 60 or Ñ = 60, could in principle be arbitrarily large. These models are straightforward to construct and are consistent at 2σ level with the observational constraints from Planck [12].…”

Section: Introductionmentioning

confidence: 95%

“…In [8], we constructed a simple inflation model in which the N and Ñ framework could differ enough so that the predictions for r corresponding to either N = 60 or Ñ = 60 are inconsistent at around 5% level. We cautioned that even such a small discrepancy could have significant implications for what we will learn from future GW experiments such as LISA, BBO and DECIGO [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Inflationary e-folding and the implications for gravitational-wave detection

Chongchitnan

2017

Preprint

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We demonstrate that the approximation for the number of inflationary e-folds commonly used in the literature can lead to highly inaccurate predictions for the amplitude of primordial gravitational waves. We show that such an approximation can lead to perfectly viable inflation models being falsely ruled out by direct or indirect gravitational-wave measurements. We illustrate this point using a new class of inflation models which include the power-law potential, V (φ) ∼ φ k , as the simplest limit. These models are simple to construct without using the slow-roll approximation, and are consistent with 2σ constraints from Planck. Crucially, these models may suffer from an order-of-magnitude error in the prediction for the gravitational-wave amplitude if the common definition of e-folding is used. Our findings have strong implications for the classes of inflation models that can be ruled out by future space-based laser interferometers such as BBO and DECIGO.

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Kinetic inflation in deformed phase space Brans–Dicke cosmology

Rasouli

Marto

Moniz

2019

Physics of the Dark Universe

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In this paper, by establishing a Brans-Dicke (BD) cosmology by means of a deformed phase space, in the absence of any scalar potential, cosmological constant and ordinary matter, we show that it is feasible to overcome obstacles reported in the corresponding commutative (nondeformed) frameworks. More concretely, by applying the Hamiltonian formalism and introducing a dynamical deformation, between the momenta associated to the FLRW scale factor and the BD scalar field, we obtain the modified equations of motion. In particular, these equations reduce to their standard counterparts when the noncommutative (NC) parameter is switched off. By focusing on a specific branch of solutions, in contrast to standard frameworks (even with a varying BD coupling parameter), we show that we can obtain an adequate appropriate inflationary epoch possessing a suitable graceful exit. In other words, in the Jordan frame (JF), such branch of solutions properly satisfy the sufficient condition required for satisfactory inflation, which is equivalent to get an inflationary phase in the conformal Einstein frame (EF) without branch change. Concerning the cosmological dynamics, we further show that our NC framework bears close resemblance to the R 2 (Starobinsky) inflationary model. 1 Recently, concerning such an ad hoc scalar potential in scalar tensor theories, it has been shown that the geometry of the higher dimensions can instead naturally yield it; see, for instance, [9,10,11,12]. Moreover, we should note that, in addition to including a scalar potential, there are also other approaches for describing the present day acceleration (which, in turn, suffer from major problems [13]): (i) When the BD coupling parameter is restricted to −2 ≤ ω ≤ −3/2; in this case, the energy condition associated to the BD scalar field is not satisfied. In this paper, to avoid encountering such a problem, we always assume −3/2 < ω. (ii) Assuming a varying BD coupling parameter [14]. (iii) Assuming that the scalar fields can interact with ordinary matter, which are called chameleon fields [15]. (iv) By starting from the BD theory in five or higher dimensional space-times, see for instance, [16]. We should emphasize that the motivation of

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Inflation model building with an accurate measure ofe-folding

Cited by 4 publications

References 16 publications

Primordial Gravitational Waves and Reheating in a New Class of Plateau-Like Inflationary Potentials

Primordial Gravitational Waves and Reheating in a New Class of Plateau-Like Inflationary Potentials

Inflationary e-folding and the implications for gravitational-wave detection

Kinetic inflation in deformed phase space Brans–Dicke cosmology

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