Bouncing scalar field cosmology in the polymeric minisuperspace. Professor ratindranath akhoury in this thesis we will discuss several issues concerning cosmological applications of noncanonical scalar elds, which are generically referred to as kessence. Similarly, the other components of the energy momentum tensor can be written, e. The dependence of gravity from the scalar field is obtained through a nonminimal coupling function which multiplies the ricci scalar in the lagrangian. The lagrangian for a scalar field is very simple and from this one can use noethers theorem in the usual way to form the energymomentum tensor and identify the density \rho and pressure p equations. Scalar field cosmology series on the foundations of natural. Perturbed selfsimilar massless scalar field in spherically.
Axially symmetric bianchi typei model with massless scalar field and cosmic strings in barbers selfcreation cosmology. Prior to the time t to, the universe was in an inflationary phase characterized by the solution 20 of the fivedimensional einstein equations with a massless real scalar field source. Generalization of qcd motivated classical su2 yangmills theory coupled to the scalar field is discussed. Abstract the generalized kleingordon equation is reconsidered in the robertsonwalker spacetime. Additionally, it touches upon the role of phantom scalar field cosmology and analyzes phantonical models. Perturbations in a coupled scalar field cosmology monthly. Tachyon scalar field in dbi and rsii cosmological context. For a scalar field theory with d spacetime dimensions, the only dimensionless parameter g n satisfies n 2d.
The evolution of scalar fields and inflationary cosmology. Relevant issues for reissnernordstromde sitter rnds black holes and borninfeldde sitter bids black holes have been discussed. Einstein field equations in the presence of mass less scalar fields for matter. For both models, we find new exact solutions for the wheelerdewitt equation and for the supersymmetric wave function equations. Dark energy as a scalar field nonminimally coupled to gravity. Massive and massless scalar field and confinement arxiv.
The region u may be a set in some euclidean space, minkowski space, or more generally a subset of a manifold, and it is typical in mathematics to impose further conditions on the field, such that it be continuous or often continuously differentiable to some order. Particularly, we analyze the late time behavior in the present matter dominated epoch of the universe. Journal of cosmology and astroparticle physics general solution of scalar field cosmology with a piecewise exponential potential to cite this article. Inflationary scenario in locally rotationally symmetric lrs bianchi type ii spacetime with massless scalar field with flat potential is discussed. Generalized hamiltonian dynamics of friedmann cosmology. We derive exact friedmannrobertsonwalker cosmological solutions in general scalar tensor gravity theories, including bransdicke gravity, for stiff matter or radiation. These solutions are considered from the standpoint of inflationary cosmology. Furthermore, we construct the unstable and center manifold of the massless scalar field cosmology motivated by the numerical results given in phys. Normal mode solutions of massless scalar field in standard. Pdf singularities in a scalar field quantum cosmology. Mar 15, 2019 vanish to recover the standard result that no particles would be created from a massless scalar field in a conformally flat spacetime. It offers new solutions and discusses its properties.
A number of new exact scalar field cosmologies are derived from effective potentials that are composed of two or more exponential terms. We give here a sufficient condition for the dispersal to take place for a scalar field that initially begins with a collapse. General solution of scalar field cosmology with a piecewise. This quantum field theory is welldefined within the framework of wightmans axioms and wightmans positive definiteness condition. We study the behavior of cosmological parameters, massive and massless scalar fields normal or phantom with a scalar potential in fr, t theory of gravity for a flat friedmannrobertsonwalker.
Inflation and the theory of cosmological perturbations. Equivalently, the brane is kept fixed at z0 while making the metric in the bulk time dependent. Pdf we study the behavior of cosmological parameters, massive and massless scalar fields normal or phantom with a scalar potential in fr. Nonstatic inhomogeneous cosmological models are obtained in general relativity for the case of a plane symmetric massless scalar field with cosmological constant. In case of massless scalar field screening solutions are found. The fluctuation of the interbrane distance implies the existence of the radion. In this case the scalar field is starting to dominate today, and mimics a cosmological constant. The phenomena of collapse and dispersal for a massless scalar field have drawn considerable interest in recent years, mainly from a numerical perspective. New exact supersymmetric wave functions for a massless scalar field and axiondilaton string cosmology in a frwl metric r. Renormalized stress tensor of a quantized massless scalar. Noncanonical scalar fields and their applications in.
Perturbations in a coupled scalar field cosmology pdf. Backreaction of the massless, minimally coupled scalar field. In particular, solutions are presented that combine eras of exponential and powerlaw growth. With the introduction of a local transformation for this field, the interaction lagrangian between the scalar field and the spinor field can be made similar to a gauge theory. Fivedimensional cosmological models with massless scalar. The case of interest here is, instead, the solution b in table 1, because this is the only critical point that allows a partition of the energy between the scalar field and the matter and contrary to c is also stable.
A curious synergy of cosmology and particle physics. Hence, a toy cosmology can be constructed along the following lines. In this work, we show a counterexample involving a class of inhomogeneous universes that are supported by a chameleon massless scalar field and exhibit anisotropic spacetime shearing effects. Then, we have a big bang model with a negative curvature scalar and a real scalar field. Whereas studied by itself, it is not explic itly used in the known completely quantizable models of matter coupled to lqg. In the current paper we apply the polymer quantization to the model of massless scalar field coupled to lqg.
We shall see that this solution gives rise, depending on the value of certain parameters, to three different spacetimes. Jan 16, 2020 we study the quantum cosmology of the 2d hawkingpage massless scalarfield model and the homogeneous and isotropic dilatonaxion string cosmology. This book presents the reduction of the friedmann equation to the abel equation, which is a very useful tool in cosmology. To get the deterministic solution in terms of cosmic time, we have assumed that the scale factor. Backreaction of a massless minimally coupled scalar field. Razmadze mathematical institute, tbilisi, 380093, georgia b bogoliubov laboratory of theoretical physics, joint institute for nuclear research, 141980 dubna, russia c laboratory of information technologies, joint institute for nuclear research, 141980. Inhomogeneous cosmological models in the presence of massless.
Citeseerx scalartensor cosmologies and their late time. We study the behavior of cosmological parameters, massive and massless scalar fields normal or phantom with a scalar potential in fr, t theory of gravity for a flat. A different approach is to modify the gravitational sector of the einstein equations. These correspond to the long or short wavelength modes respectively of massless scalar fields. In scalar tensor theories the gravitational interaction is affected by both a scalar and a tensor field. Scalar field and all that supernova cosmology project. Indeed, it is wellknown that for isotropic cosmological models, for a given dependence of the cosmological radius on time it is always possible to construct a potential for a minimally coupled scalar eld in brief. Pdf axially symmetric bianchi typei model with massless. Interactions in scalar field cosmology arxiv vanity. Cosmology with a continuous tower of scalar fields. Request pdf renormalized stress tensor of a quantized massless scalar field in warped cosmological braneworld background energy momentum tensor of a conformally coupled quantum scalar field in. We assume the bunchdavies vacuum during inflation and then use a sudden matching approximation to match it onto a radiation era and subsequently onto a matter era. Propagation of massless scalar field in standardlike. New exact supersymmetric wave functions for a massless scalar.
We first study a massless scalar field in an open universe. General relativity and quantum cosmology authorstitles new. Cosmological backreaction of a quantized massless scalar field. An alternative to the conventional reheating model, in which the scalar fields energy is transferred to the matter due to scalar field oscillations, is the warm inflationary model 29, 30, 20 in which an interaction term is significant throughout the inflationary regime not just after slowroll and so the energy of the scalar field is.
Aspects of cosmology with scalar fields paris supernova. For example, in d 4, only g 4 is classically dimensionless, and so the only classically scaleinvariant scalar field theory in d 4 is the massless. Lrs bianchi typev cosmological model for barotropic fluid. Oct 02, 2012 the polymer quantization of matter fields is a diffeomorphism invariant framework compatible with loop quantum gravity. Mathematically, scalar fields on a region u is a real or complexvalued function or distribution on u. Generalized hamiltonian dynamics of friedmann cosmology with scalar and spinor matter source fields a. The result of damour and nordtvedt that for a massless scalar in a flat cosmology the universe evolves towards a state indistinguishable from general relativity is generalized. We study a cosmological setup consisting of a frw metric as the background geometry with a massless scalar field in the framework. Jun 10, 20 if one considers one compact extra dimension, a massless scalar field leads to a spectrum in the 4 large noncompact dimensions consisting of a massless scalar field plus a discrete tower of massive scalar fields, being the corresponding masses determined by the compactification scale of the extra dimension. We discuss the boundary conditions of the resulting perturbed solutions.
New exact supersymmetric wave functions for a massless. The topology and the values of the three free parameters of the model are constrained by imposing a positive energy density. Radion a massless scalar field that causes a distortion of the bulk geometry. A simple condition on the parameters of the cosmological model that is satisfied in standard cosmology is determined such that the massless scalar field has a tailfree propagation, that is it entirely propagates on the light cones. Cosmology on the brane is obtained by allowing the brane to move in the bulk. We show that the wheelerdewitt equations for the hawkingpage model and the axiondilaton string cosmology. The massive scalar field, corresponding the scalar glueball, provides a confining potential for static, pointlike, external sources.
Noncanonical scalar fields and their applications in cosmology and astrophysics by christopher s. Quantum field theory of a free massless pseudoscalar field. In this paper, we investigate the linear perturbations of the spherically symmetric spacetimes with kinematic selfsimilarity of the second kind. The separated time equation is integrated in the massless case by assuming the cosmological background of the standard cosmology. If present, the long wavelength modes of such fields would be expected to dominate the energy density of the universe. Lagrange density for massless scalar field duplicate ask question asked 2 years, 10 months ago. Lrs bianchi type ii inflationary universe with massless. Fivedimensional anisotropic dark energy cosmological model in. The matter content is represented by a minimally coupled, massless, scalar field. Higgs field and the massless minimally coupled scalar field. Luca amendolaw 0 0 osservatorio astronomico di roma, viale parco mellini 84, 006 roma, italy a b s t r a c t i analyse the density perturbations in a cosmological model with a scalar field coupled to ordinary matter, such as one obtains in string theory and in conformally transformed scalartensor theories. So the scalar field in general must know about the curvature of the metric in order to compensate this. The massless scalar field equations are solved which yield the background and an exact solutions for the perturbed equations.