S. Yu. Vernov
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View article: More accurate slow-roll approximations for inflation in scalar-tensor theories
More accurate slow-roll approximations for inflation in scalar-tensor theories Open
We propose new versions of the slow-roll approximation for inflationary models with nonminimally coupled scalar fields. We derive more precise expressions for the standard slow-roll parameters as functions of the scalar field. To verify th…
View article: Superpotential method and the amplification of inflationary perturbations
Superpotential method and the amplification of inflationary perturbations Open
peer reviewed
View article: New Integrable Chiral Cosmological Models with Two Scalar Fields
New Integrable Chiral Cosmological Models with Two Scalar Fields Open
We construct integrable chiral cosmological models with two scalar fields and potentials represented in terms of hyperbolic functions. Using the conformal transformation of the metric and the corresponding models with induced gravity terms…
View article: Integrable Cosmological Models with an Arbitrary Number of Scalar Fields
Integrable Cosmological Models with an Arbitrary Number of Scalar Fields Open
We consider cosmological models with an arbitrary number of scalar fields nonminimally coupled to gravity and construct new integrable cosmological models. In the constructed models, the Ricci scalar is an integral of motion irrespectively…
View article: Primordial Black Holes in Induced Gravity Inflationary Models with Two Scalar Fields
Primordial Black Holes in Induced Gravity Inflationary Models with Two Scalar Fields Open
We propose a two-field inflationary model with the induced gravity term. Using conformal transformation of the metric, we get the chiral cosmological model with two scalar fields. We demonstrate that the constructed inflationary model does…
View article: Superpotential method and the amplification of inflationary perturbations
Superpotential method and the amplification of inflationary perturbations Open
The superpotential method is a reconstruction technique which has proven useful to build exact cosmological solutions. We here employ the superpotential method in order to reconstruct the features necessary for the inflaton potential to dr…
View article: New slow-roll approximations for inflation in Einstein-Gauss-Bonnet gravity
New slow-roll approximations for inflation in Einstein-Gauss-Bonnet gravity Open
We propose new slow-roll approximations for inflationary models with the Gauss-Bonnet term. We find more accurate expressions of the standard slow-roll parameters as functions of the scalar field. To check the accuracy of approximations co…
View article: Construction of Chiral Cosmological Models Unifying Inflation and Primordial Black Hole Formation
Construction of Chiral Cosmological Models Unifying Inflation and Primordial Black Hole Formation Open
We propose the method for construction of $F(R,ξ)$ gravity model, unifying inflation and primordial black hole formation. The proposed models are based on the Starobinsky $R+R^2$ inflationary model, so, the function $F(R,ξ)$ is a quadratic…
View article: Cosmological Solutions of Integrable F(R) Gravity Models with an Additional Scalar Field
Cosmological Solutions of Integrable F(R) Gravity Models with an Additional Scalar Field Open
We consider F(R) cosmological models with a scalar field. For the R2 model in the spatially flat Friedmann–Lemaître–Robertson–Walker metric, the Ricci scalar R can smoothly change its sign during the evolution if an…
View article: String-Inspired Correction to R2 Inflation
String-Inspired Correction to R2 Inflation Open
We study the Starobinsky–Bel–Robinson inflationary model in the slow-roll regime. In the framework of higher-curvature corrections to inflationary parameters, we estimate the maximal possible value of the dimensionless positive…
View article: On Extensions of the Starobinsky Model of Inflation
On Extensions of the Starobinsky Model of Inflation Open
We propose inflationary models that are one-parametric generalizations of the Starobinsky R+R2 model. Using the conformal transformation, we obtain scalar field potentials in the Einstein frame that are one-parametric generalizations of th…
View article: Anisotropic solutions for $R^2$ gravity model with a scalar field
Anisotropic solutions for $R^2$ gravity model with a scalar field Open
We study anisotropic solutions for the pure $R^2$ gravity model with a scalar field in the Bianchi I metric. The evolution equations have a singularity at zero value of the Ricci scalar $R$ for anisotropic solutions, whereas these equation…
View article: New one-parametric extension of the Starobinsky inflationary model
New one-parametric extension of the Starobinsky inflationary model Open
We propose a one-parametric extension of the Starobinsky $R+R^2$ model by adding the $(R+m^2β^2)^{3/2}$ term. The parameter $m$ is the inflaton mass, which is determined in the same way as in the Starobinsky model, and $β$ is a dimensionle…
View article: On the superstring-inspired quantum correction to the Starobinsky model of inflation
On the superstring-inspired quantum correction to the Starobinsky model of inflation Open
Superstring/M-theory is the theory of quantum gravity that can provide the UV-completion to viable inflation models. We modify the Starobinsky inflation model by adding the Bel-Robinson tensor $T^{μνλρ}$ squared term proposed as the leadin…
View article: Analytic extensions of Starobinsky model of inflation
Analytic extensions of Starobinsky model of inflation Open
We study several extensions of the Starobinsky model of inflation, which obey all observational constraints on the inflationary parameters, by demanding that both the inflaton scalar potential in the Einstein frame and the F ( R ) gravity …
View article: De Sitter Solutions in Models with the Gauss-Bonnet Term
De Sitter Solutions in Models with the Gauss-Bonnet Term Open
De Sitter solutions play an important role in cosmology because the knowledge of unstable de Sitter solutions can be useful in describing inflation, whereas stable de Sitter solutions are often used in models of the late-time acceleration …
View article: Inflation with a quartic potential in the framework of Einstein-Gauss-Bonnet gravity
Inflation with a quartic potential in the framework of Einstein-Gauss-Bonnet gravity Open
We investigate inflationary dynamics in the framework of the\nEinstein-Gauss-Bonnet gravity. In the model under consideration, the inflaton\nfield is non-minimally coupled to the Gauss-Bonnet curvature invariant, so that\nthe latter appear…
View article: Stability analysis of de Sitter solutions in models with the Gauss-Bonnet term
Stability analysis of de Sitter solutions in models with the Gauss-Bonnet term Open
We investigate the scalar field dynamics of models with nonminimally coupled\nscalar fields in the presence of the Gauss-Bonnet term and derive the structure\nof the effective potential and conditions for stable de Sitter solutions in\ngen…
View article: Superpotential method for chiral cosmological models connected with modified gravity
Superpotential method for chiral cosmological models connected with modified gravity Open
We consider the Chiral Cosmological Models (CCMs) and modified gravity theories associated with them. Generalization of the superpotential method for a general CCM with several scalar fields is performed, and the method of construction CCM…
View article: Duality between static spherically or hyperbolically symmetric solutions and cosmological solutions in scalar-tensor gravity
Duality between static spherically or hyperbolically symmetric solutions and cosmological solutions in scalar-tensor gravity Open
We study static spherically and hyperbolically symmetric solutions of the Einstein equations in the presence of a conformally coupled scalar field and compare them with those in the space filled with a minimally coupled scalar field. We th…
View article: Exact spherically symmetric and hyperbolically symmetric static solutions and Kantowski-Sachs universes for conformally coupled scalar fields
Exact spherically symmetric and hyperbolically symmetric static solutions and Kantowski-Sachs universes for conformally coupled scalar fields Open
We study static spherically and hyperbolically symmetric solutions of the Einstein equations in the presence of a conformally coupled scalar field and compare them with those in the space filled with a minimally coupled scalar field. We al…
View article: De Sitter and power-law solutions in non-local Gauss–Bonnet gravity
De Sitter and power-law solutions in non-local Gauss–Bonnet gravity Open
The cosmological dynamics of a non-locally corrected gravity theory, involving a power of the inverse d’Alembertian, is investigated. Casting the dynamical equations into local form, the fixed points of the models are derived, as well as c…
View article: MSSM inflation and cosmological attractors
MSSM inflation and cosmological attractors Open
Inflationary scenarios motivated by the minimal supersymmetric standard model (MSSM) where five scalar fields are non-minimally coupled to gravity are considered. The potential of the model and the function of non-minimal coupling are poly…
View article: Induced gravity and minimally and conformally coupled scalar fields in Bianchi-I cosmological models
Induced gravity and minimally and conformally coupled scalar fields in Bianchi-I cosmological models Open
We study the cosmological evolution and singularity crossing in the Bianchi-I\nuniverse filled with a conformally coupled scalar field and compare them with\nthose of the Bianchi-I universe filled with a minimally coupled scalar field.\n W…
View article: Multifield Inflation Scenarios from MSSM
Multifield Inflation Scenarios from MSSM Open
first_page settings Order Article Reprints Font Type: Arial Georgia Verdana Font Size: Aa Aa Aa Line Spacing: Column Width: Background: Open AccessAbstract Multifield Inflation Scenarios from MSSM † by Ekaterina Pozdeeva 1,* an…
View article: Integrable cosmological models in the Einstein and in the Jordan frames and Bianchi-I cosmology
Integrable cosmological models in the Einstein and in the Jordan frames and Bianchi-I cosmology Open
We study integrable models in the Bianchi I metric case with scalar fields minimally and non-minimally coupled with gravity and the correspondence between their general solutions. Using the model with a minimally coupled scalar field and a…
View article: Bianchi-I cosmological model and crossing singularities
Bianchi-I cosmological model and crossing singularities Open
We consider a rather simple method for the description of the big bang-big crunch cosmological singularity crossing. For the flat Friedmann universe this method gives the same results as more complicated methods, usingWeyl symmetry or the …
View article: Transformations between Jordan and Einstein frames: Bounces, antigravity, and crossing singularities
Transformations between Jordan and Einstein frames: Bounces, antigravity, and crossing singularities Open
We study the relation between the Jordan-Einstein frame transition and the\npossible description of the crossing of singularities in flat Friedmann\nuniverses, using the fact that the regular evolution in one frame can\ncorrespond to cross…
View article: Travelling between Jordan and Einstein frames, bounces, antigravity and sailing through singularities
Travelling between Jordan and Einstein frames, bounces, antigravity and sailing through singularities Open
We study the relation between the Jordan-Einstein frame transition and the possible description of the crossing of singularities, using the fact that the regular evolution in one frame can correspond to crossing singularities in the other …