Anisotropic hyperbolic inflation

Chen, Chong-Bin; Soda, Jiro

doi:10.1088/1475-7516/2021/09/026

Cited by 17 publications

(9 citation statements)

References 60 publications

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“…We will have more to say about this in [30]. 11 See [31,32] for some recent discussions on anisotropic inflation in the early Universe.…”

Section: H0-diagnostics Adapted To Distance Observablesmentioning

confidence: 99%

$H_0$ as a Universal FLRW Diagnostic

Krishnan¹,

Mondol²

2022

Preprint

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We reverse the logic behind the apparent existence of H0-tension, to design diagnostics for cosmological models. The basic idea is that the non-constancy of H0 inferred from observations at different redshifts is a null hypothesis test for models within the FLRW paradigm -if H0 runs, the model is wrong. Depending on the kind of observational data, the most suitable form of the diagnostic can vary. As examples, we present two H0 diagnostics that are adapted to two different BAO observables. We use these and the corresponding BAO data to Gaussian reconstruct the running of H0 in flat ΛCDM with Planck values for the model parameters. For flat ΛCDM when the radiation contribution can be neglected, with comoving distance data, the diagnostic is a simple hypergeometric function. Possible late time deviations from the FLRW paradigm can also be accommodated, by simply keeping track of the (potentially anisotropic) sky variation of the diagnostic.

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“…We will have more to say about this in [30]. 11 See [31,32] for some recent discussions on anisotropic inflation in the early Universe.…”

Section: H0-diagnostics Adapted To Distance Observablesmentioning

confidence: 99%

$H_0$ as a Universal FLRW Diagnostic

Krishnan¹,

Mondol²

2022

Preprint

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“…This is in contrast to the quintom model in which the kinetic components define the two-dimensional flat space [29]. This specific two-scalar field model has been widely studied in the literature [30][31][32][33], and various extensions for which the scalar fields may have negative energy density have been proposed before [34,35].…”

Section: Introductionmentioning

confidence: 99%

Analytic Solution and Noether Symmetries for the Hyperbolic Inflationary Model in the Jordan Frame

Paliathanasis

2022

Universe

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The Noether symmetry analysis is applied for the study of a multifield cosmological model in a spatially flat FLRW background geometry. The gravitational Action Integral consists of two scalar fields, the Brans–Dicke field and a second scalar field minimally coupled to gravity. However, the two scalar fields interact in kinetic terms. This multifield has been found to describe the equivalent of hyperbolic inflation in the Jordan frame. The application of Noether’s theorems constrains the free parameters of the model so that conservation laws exist. We find that the field equations form an integrable dynamical system, and the analytic solution is derived.

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“…In this paper we shall adopt the last line of research and we shall formalize anisotropic inflation [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] in the context of modified gravity. The most natural generalization of the isotropic FRW geometry is provided by the Bianchi metrics classification.…”

Section: Introductionmentioning

confidence: 99%

Formalizing Anisotropic Inflation in Modified Gravity

Nojiri¹,

Odintsov²,

Oikonomou³

et al. 2022

Preprint

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Motivated by the fact that the pre-inflationary era may evolve in an exotic way, in this work we formalize anisotropic evolution in the context of modified gravity, focusing on pre-inflationary and near the vicinity of the inflationary epochs. We specialize on specific metrics like Bianchi and Taub and we formalize the inflationary theory in vacuum F (R) gravity, in F (R) gravity with an extra scalar field and in Gauss-Bonnet gravity. We discuss the qualitative effects of the anisotropies on the evolution of the Universe and also we consider several specific solutions, like the de Sitter solution, in both the isotropic and anisotropic contexts. Furthermore, several exotic modified gravity cosmological solutions, like the ones which contain finite time singularities, are also discussed in brief.

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Anisotropic hyperbolic inflation

Cited by 17 publications

References 60 publications

$H_0$ as a Universal FLRW Diagnostic

$H_0$ as a Universal FLRW Diagnostic

Analytic Solution and Noether Symmetries for the Hyperbolic Inflationary Model in the Jordan Frame

Formalizing Anisotropic Inflation in Modified Gravity

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