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Inflationary cosmology is the leading explanation of the very early universe. Many different models of inflation have been constructed which fit current observational data. In this work theoretical and numerical methods for constraining the…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-29 Ian Huston

The early Universe inflation is well known as a promising theory to explain the origin of large scale structure of the Universe, a causal theory for the origin of primordial density fluctuations which may explain the observed density…

Astrophysics · Physics 2007-05-23 Xin-he Meng

A theory of evolution for the Universe requires both a mutation mechanism and a selection mechanism. We propose that both can be encountered in the stochastic approach to quantum cosmology. In Brans--Dicke chaotic inflation, the quantum…

Astrophysics · Physics 2009-10-22 Juan Garcia-Bellido

According to the Brans--Dicke theory, the value of the gravitational constant G which we measure at present is determined by the value of the Brans--Dicke scalar field \phi at the end of inflation. However, due to quantum fluctuations of…

Astrophysics · Physics 2009-09-29 Juan Garcia-Bellido , Andrei Linde , Dmitri Linde

We propose a model for cosmic inflation which is based on an effective description of strongly interacting, nonsupersymmetric matter within the framework of dynamical Abelian projection and centerization. The underlying gauge symmetry is…

High Energy Physics - Phenomenology · Physics 2009-11-07 Ralf Hofmann , Mathias Th. Keil

The general Poincar\'e gauge cosmology given by a nine-parameter gravitational Lagrangian with ghost- and tachyon-free conditions is studied from the perspective of field theory. By introducing new variables for replacing two (pseudo-)…

General Relativity and Quantum Cosmology · Physics 2020-10-14 Hongchao Zhang , Lixin Xu

A gauge-invariant, linear cosmological perturbation theory of an almost homogeneous and isotropic universe with dynamically evolving Newton constant G and cosmological constant $\Lambda$ is presented. The equations governing the evolution…

General Relativity and Quantum Cosmology · Physics 2011-04-22 Adriano Contillo

Observational cosmology provides us with a large number of high precision data which are used to derive models trying to reproduce ``on the mean'' our observable patch of the Universe. Most of these attempts are achieved in the framework of…

Astrophysics · Physics 2011-11-10 Marie-Noëlle Célérier

The problem of making predictions in eternally inflating universe that thermalizes by bubble nucleation is considered. A recently introduced regularization procedure is applied to find the probability distribution for the ensemble of…

Astrophysics · Physics 2009-10-28 Alexander Vilenkin , Serge Winitzki

Non-linear interactions during inflation generate non-Gaussianities in the distribution of primordial curvature. In many theories, the physics is scale-invariant, such that the induced three-point function depends solely on a dimensionless…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-27 Oliver H. E. Philcox

Cosmological local observables are at best statistically determined by the fundamental theory describing inflation. When the scalar inflaton is coupled uniformly to a collection of subdominant massless gauge vectors, rotational invariance…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-07 Mikjel Thorsrud , David F. Mota , Federico R. Urban

We investigate the cosmic inflation within a class of the scalar-tensor model with the scalar-dependent non-minimal kinetic couplings. The inflationary dynamical potential will be applied. Using the slow-roll approximation, we compute…

General Relativity and Quantum Cosmology · Physics 2025-12-01 Feyzollah Younesizadeh , Davoud Kamani

I describe a recently derived stochastic approach to inflaton dynamics which can address some serious problems associated with conventional inflationary theory. Using this theory I derive an exact solution to the stochastic dynamics for the…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Andrew Matacz

The standard field-theoretical approach to the slow-roll inflation is introduced. We then show as, in order to calculate the mean square of the canonical gauge invariant quantum fluctuations associated to a generic field, the logarithm of…

High Energy Physics - Theory · Physics 2013-01-08 F. Finelli , G. Marozzi , A. A. Starobinsky , G. P. Vacca , G. Venturi

We derive a stochastic wave equation for an inflaton in an environment of an infinite number of fields. We study solutions of the linearized stochastic evolution equation in an expanding universe. The Fokker-Planck equation for the inflaton…

High Energy Physics - Theory · Physics 2018-07-25 Z. Haba

The theory of cosmic inflation has received a great amount of deserved attention in recent years due to it's stunning predictions about the early universe. Alongside the usual cold inflation paradigm, warm inflation has garnered a huge…

General Relativity and Quantum Cosmology · Physics 2024-08-02 Oem Trivedi

We consider the cosmological dynamics associated with volume weighted measures of eternal inflation, in the Bousso-Polchinski model of the string theory landscape. We find that this measure predicts that observers are most likely to find…

High Energy Physics - Theory · Physics 2008-11-26 Timothy Clifton , Stephen Shenker , Navin Sivanandam

We consider a scenario where the strong coupling constant was changing in the early universe. We attribute this change to a variation in the colour charge within a Bekenstein-like model. Treating the vacuum gluon condensate $<G^2>$ as a…

Astrophysics · Physics 2007-05-23 N. Chamoun , S. J. Landau , H. Vucetich

Inflationary cosmology has made significant strides in understanding the physics driving the rapid expansion of the early universe. However, many inflation models with diverse potential shapes present analysis, comparison, and…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-25 Somnath Das , P K Suresh

Analysis of regular inflationary cosmological models with two torsion functions filled with scalar field with quadratic potential and ultrarelativistic matter is carried out numerically. Properties of different stages of regular…

General Relativity and Quantum Cosmology · Physics 2014-11-18 A. S. Garkun , V. I. Kudin , A. V. Minkevich