Power-Law Expansion and Scalar Field Cosmology in Higher Derivative Theory

We consider a generalized Brans–Dicke model in which the scalar field has a self-interacting potential function. The scalar field is also allowed to couple nonminimally with the matter part. We assume that it has a chameleon behavior in the sense that it acquires a density-dependent effective mass. We consider two different types of matter systems which couple with the chameleon, dust and vacuum. In the first case, we find a set of exact solutions when the potential has an exponential form. In the second case, we find a power-law exact solution for the scale factor. In this case, we will show that the vacuum density decays during expansion due to coupling with the chameleon.

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Quantization of Einstein-aether scalar field cosmology

The European Physical Journal C ◽

10.1140/epjc/s10052-021-08933-z ◽

2021 ◽

Vol 81 (2) ◽

Author(s):

N. Dimakis ◽

T. Pailas ◽

A. Paliathanasis ◽

G. Leon ◽

Petros A. Terzis ◽

...

Keyword(s):

Scalar Field ◽

Classical Solution ◽

Potential Function ◽

Scalar Fields ◽

Inflationary Model ◽

Cosmological Theory ◽

Local Functions ◽

Arbitrary Potential ◽

Scalar Field Cosmology ◽

First Time

AbstractWe present, for the first time, the quantization process for the Einstein-aether scalar field cosmology. We consider a cosmological theory proposed as a Lorentz violating inflationary model, where the aether and scalar fields interact through the assumption that the aether action constants are ultra-local functions of the scalar field. For this specific theory there is a valid minisuperspace description which we use to quantize. For a particular relation between the two free functions entering the reduced Lagrangian the solution to the Wheeler–DeWitt equation as also the generic classical solution are presented for any given arbitrary potential function.

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Modern Topics in Scalar Field Cosmology

10.23889/suthesis.56561 ◽

2020 ◽

Author(s):

◽

Cari Powell

Keyword(s):

Dark Matter ◽

Scalar Field ◽

Gravitational Wave ◽

Gravitational Waves ◽

Mass Range ◽

Distant Future ◽

Field System ◽

Stochastic Background ◽

Scalar Field Cosmology

The aim of this research is to use modern techniques in scalar ﬁeld Cosmol-ogy to produce methods of detecting gravitational waves and apply them to current gravitational waves experiments and those that will be producing results in the not too distant future. In the ﬁrst chapter we discuss dark matter and some of its candidates, speciﬁcally, the axion. We then address its relationship with gravitational waves. We also discuss inﬂation and how it can be used to detect gravitational waves. Chapter 2 concentrates on constructing a multi ﬁeld system of axions in order to increase the mass range of the ultralight axion, putting it into the observation range of pul-sar timing arrays. Chapter 3 discusses non-attractor inﬂation which is able to enhance stochastic background gravitational waves at scales that allows them to be measured by gravitational wave experiments. Chapter 4 uses a similar method to chapter 3 and applies it to 3-point overlap functions for tensor, scalar and a combination of the two polarisations.

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Regular and Chaotic Regimes in Scalar Field Cosmology

Symmetry Integrability and Geometry Methods and Applications ◽

10.3842/sigma.2006.037 ◽

2006 ◽

Cited By ~ 2

Author(s):

Alexey V. Toporensky

Keyword(s):

Scalar Field ◽

Scalar Field Cosmology

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Evolution of anisotropic cosmic models in f(R,ϕ) gravity

International Journal of Modern Physics D ◽

10.1142/s0218271818501158 ◽

2018 ◽

Vol 27 (12) ◽

pp. 1850115 ◽

Cited By ~ 2

Author(s):

M. Zubair ◽

Farzana Kousar ◽

Saira Waheed

Keyword(s):

Scalar Field ◽

Power Law ◽

Bianchi Type ◽

Scalar Potential ◽

Anisotropic Fluid ◽

Type I ◽

Field Equations ◽

Eos Parameter ◽

Free Parameters ◽

Physical Quantities

In this paper, we will discuss cosmological models using Bianchi type I for anisotropic fluid in [Formula: see text] theory of gravity which involves scalar potential. For this purpose, we consider power law assumptions of coupling function and scalar field along with the proportionality condition of expansion and shear scalars. We choose two [Formula: see text] models and obtain exact solutions of field equations in both cases. For these constructed models, the behavior of different physical quantities like EoS parameter, self-interacting potential as well as deceleration and skewness parameters are explored and illustrated graphically for the feasible ranges of free parameters. It is concluded that anisotropic fluid approaches isotropy in later cosmic times for both models.

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