scholarly journals One-loop quantum corrections to cosmological scalar field potentials

2007 ◽  
Vol 75 (6) ◽  
Author(s):  
Alexandre Arbey ◽  
Farvah Mahmoudi
Keyword(s):  
Scalar Field ◽  
Quantum Corrections ◽  
Field Potentials ◽  
Cosmological Scalar

scholarly journals Quantum corrections to slow-roll inflation: scalar and tensor modes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jens O. Andersen ◽  
Magdalena Eriksson ◽  
Anders Tranberg
Keyword(s):  
Scalar Field ◽  
Quantum Corrections ◽  
Tree Level ◽  
Field Equations ◽  
Slow Roll ◽  
Scalar Field Equations ◽  
Slow Rolling ◽  
Different Sources ◽  
Suitable Potential ◽  
Quadratic Order

Abstract Inflation is often described through the dynamics of a scalar field, slow-rolling in a suitable potential. Ultimately, this inflaton must be identified with the expectation value of a quantum field, evolving in a quantum effective potential. The shape of this potential is determined by the underlying tree-level potential, dressed by quantum corrections from the scalar field itself and the metric perturbations. Following [1], we compute the effective scalar field equations and the corrected Friedmann equations to quadratic order in both scalar field, scalar metric and tensor perturbations. We identify the quantum corrections from different sources at leading order in slow-roll, and estimate their magnitude in benchmark models of inflation. We comment on the implications of non-minimal coupling to gravity in this context.

scholarly journals Dynamics of scalar potentials in theory of gravity

2019 ◽  
Vol 97 (8) ◽  
pp. 880-894
Author(s):  
M. Zubair ◽  
Farzana Kousar ◽  
Saira Waheed
Keyword(s):  
Scalar Field ◽  
Field Potential ◽  
Graphical Analysis ◽  
Chaplygin Gas ◽  
Field Potentials ◽  
De Sitter ◽  
Field Equations ◽  
Barotropic Fluid ◽  
First Case ◽  
De Sitter Universe

In this paper, we explore the nature of scalar field potential in [Formula: see text] gravity using a well-motivated reconstruction scheme for flat Friedmann–Robertson–Walker (FRW) geometry. The beauty of this scheme lies in the assumption that the Hubble parameter can be expressed in terms of scalar field and vice versa. Firstly, we develop field equations in this gravity and present some general explicit forms of scalar field potential via this technique. In the first case, we take the de Sitter universe model and construct some field potentials by taking different cases for the coupling function. In the second case, we derive some field potentials using the power law model in the presence of different matter sources like barotropic fluid, cosmological constant, and Chaplygin gas for some coupling functions. From graphical analysis, it is concluded that using some specific values of the involved parameters, the reconstructed scalar field potentials are cosmologically viable in both cases.

scholarly journals Tachyonic matter cosmology with exponential and hyperbolic potentials

2017 ◽  
Vol 26 (02) ◽  
pp. 1750012 ◽  
Author(s):  
B. Pourhassan ◽  
J. Naji
Keyword(s):  
Scalar Field ◽  
Observational Data ◽  
Cosmological Parameters ◽  
Field Potentials ◽  
Exponential Potential ◽  
Frw Universe ◽  
Hyperbolic Cosine ◽  
Special Cases ◽  
Friedmann Robertson Walker ◽  
Type Potential

In this paper, we consider tachyonic matter in spatially flat Friedmann–Robertson–Walker (FRW) universe, and obtain behavior of some important cosmological parameters for two special cases of potentials. First, we assume the exponential potential and then consider hyperbolic cosine type potential. In both cases, we obtain behavior of the Hubble, deceleration and EoS parameters. Comparison with observational data suggest the model with hyperbolic cosine type scalar field potentials has good model to describe universe.

scholarly journals Generalized scalar field potentials and inflation

1995 ◽  
Vol 51 (12) ◽  
pp. 6757-6763 ◽  
Author(s):  
Paul Parsons ◽  
John D. Barrow
Keyword(s):  
Scalar Field ◽  
Field Potentials

Geometric phase of cosmological scalar and tensor perturbations in f(R) gravity

2018 ◽  
Vol 33 (14) ◽  
pp. 1850077
Author(s):  
Hamideh Balajany ◽  
Mohammad Mehrafarin
Keyword(s):  
Scalar Field ◽  
Harmonic Oscillator ◽  
Geometric Phase ◽  
Berry Phase ◽  
Time Dependent ◽  
Einstein Theory ◽  
Tensor Perturbations ◽  
Cosmological Scalar ◽  
Conformal Equivalence

By using the conformal equivalence of f(R) gravity in vacuum and the usual Einstein theory with scalar-field matter, we derive the Hamiltonian of the linear cosmological scalar and tensor perturbations in f(R) gravity in the form of time-dependent harmonic oscillator Hamiltonians. We find the invariant operators of the resulting Hamiltonians and use their eigenstates to calculate the adiabatic Berry phase for sub-horizon modes as a Lewis–Riesenfeld phase.

scholarly journals Gravitational Baryogenesis in Hořava–Lifshitz gravity

2019 ◽  
Vol 34 (25) ◽  
pp. 1950203 ◽  
Author(s):  
Sayani Maity ◽  
Prabir Rudra
Keyword(s):  
Quantum Theory ◽  
Scalar Field ◽  
Chaplygin Gas ◽  
Quantum Corrections ◽  
Theory Of Gravity

In this work, we intend to address the matter–antimatter asymmetry via the gravitational baryogenesis mechanism in the background of a quantum theory of gravity. We investigate this mechanism under the framework of Hořava–Lifshitz gravity. We will compute the baryon-to-entropy ratio in the chosen framework and investigate its physical viability against the observational bounds. We also conduct the above study for various sources of matter like scalar field and Chaplygin gas as specific examples. We speculate that quantum corrections from the background geometry will lead to interesting results.

scholarly journals Reconstructing f(R) gravity from a Chaplygin scalar field in de Sitter spacetimes

2018 ◽  
Vol 15 (02) ◽  
pp. 1850027 ◽  
Author(s):  
Heba Sami ◽  
Neo Namane ◽  
Joseph Ntahompagaze ◽  
Maye Elmardi ◽  
Amare Abebe
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Field Model ◽  
Exact Formula ◽  
Chaplygin Gas ◽  
Reconstruction Technique ◽  
Field Potentials ◽  
De Sitter ◽  
Cosmological Expansion ◽  
Lagrangian Densities

We present a reconstruction technique for models of [Formula: see text] gravity from the Chaplygin scalar field in flat de Sitter spacetimes. Exploiting the equivalence between [Formula: see text] gravity and scalar–tensor (ST) theories, and treating the Chaplygin gas (CG) as a scalar field model in a universe without conventional matter forms, the Lagrangian densities for the [Formula: see text] action are derived. Exact [Formula: see text] models and corresponding scalar field potentials are obtained for asymptotically de Sitter spacetimes in early and late cosmological expansion histories. It is shown that the reconstructed [Formula: see text] models all have General Relativity (GR) as a limiting solution.

POWER-LOW EXPANSION IN k-ESSENCE COSMOLOGY

2004 ◽  
Vol 19 (10) ◽  
pp. 761-768 ◽  
Author(s):  
LUIS P. CHIMENTO ◽  
ALEXANDER FEINSTEIN
Keyword(s):  
Gravitational Field ◽  
Scalar Field ◽  
Field Model ◽  
Constant Function ◽  
Field Potentials ◽  
Field Equations ◽  
Large Window ◽  
The Family ◽  
Stable Solutions ◽  
Linear Scalar

We study spatially flat isotropic universes driven by k-essence. It is shown that Friedmann and k-field equations may be analytically integrated for arbitrary k-field potentials during evolution with a constant baryotropic index. It follows that there is an infinite number of dynamically different k-theories with equivalent kinematics of the gravitational field. We show that there is a large "window" of stable solutions, and that the dust-like behavior separates stable from unstable expansion. Restricting to the family of power law solutions, it is argued that the linear scalar field model, with constant function F, is isomorphic to a model with divergent speed of sound and this makes them less suitable for cosmological modeling than the nonlinear k-field solutions we find in this paper.

scholarly journals Nonminimal kinetic coupled gravity: Inflation on the warped DGP brane

2016 ◽  
Vol 31 (10) ◽  
pp. 1650047
Author(s):  
F. Darabi ◽  
A. Parsiya ◽  
K. Atazadeh
Keyword(s):  
Scalar Field ◽  
Coupling Constants ◽  
Kinetic Term ◽  
Field Potentials ◽  
Coupling Constant ◽  
Field Equations ◽  
Einstein Tensor ◽  
Brane Model ◽  
Walker Metric ◽  
Friedmann Robertson Walker

We consider the nonminimally kinetic coupled version of DGP brane model, where the kinetic term of the scalar field is coupled to the metric and Einstein tensor on the brane by a coupling constant [Formula: see text]. We obtain the corresponding field equations, using the Friedmann–Robertson–Walker metric and the perfect fluid, and study the inflationary scenario to confront the numerical analysis of six typical scalar field potentials with the current observational results. We find that among the suggested potentials and coupling constants, subject to the e-folding [Formula: see text], the potentials [Formula: see text], [Formula: see text] and [Formula: see text] provide the best fits with both Planck+WP+highL data and Planck+WP+highL+BICEP2 data.

scholarly journals QUANTUM CORRECTIONS TO NEWTON'S LAW

2002 ◽  
Vol 17 (36) ◽  
pp. 2371-2381 ◽  
Author(s):  
B. F. L. WARD
Keyword(s):  
Scalar Field ◽  
Quantum Gravity ◽  
Quantum Corrections ◽  
New Approach ◽  
Newton's Law ◽  
Newton’S Law

We present a new approach to quantum gravity starting from Feynman's formulation for the simplest example, that of a scalar field as the representative matter. We show that we extend his treatment to a calculable framework using resummation techniques already well-tested in other problems. Phenomenological consequences for Newton's law are described.

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