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Inflationary Cosmology makes the universe ``eternal" and provides for recurrent universe creation, ad infinitum -- making it also plausible to assume that ``our" Big Bang was also preceeded by others, etc.. However, GR tells us that in the…

High Energy Physics - Theory · Physics 2008-11-26 Yuval Ne'eman

There are at least two cosmological constants calling for explanation. The first one describes the quasi-de Sitter inflation in the early universe, and the second describes the current acceleration of the universe associated with dark…

High Energy Physics - Theory · Physics 2024-05-01 Igor Volovich

At its very beginning, the universe is believed to have grown exponentially in size via the mechanism of inflation. The almost scale-invariant density perturbation spectrum predicted by inflation is strongly supported by cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 David F. Chernoff , S. -H. Henry Tye

We have considered a cosmological model with a phenomenological model for the cosmological constant of the form $\Lambda=\bt\fr{\ddot R}{R}$, $ \bt$ is a constant. For age parameter consistent with observational data the Universe must be…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Arbab I. Arbab

In order to solve the fine-tuning problem of the cosmological constant, we propose a simple model with the vacuum energy non-minimally coupled to the inflaton field. In this model, the vacuum energy decays to the inflaton during…

General Relativity and Quantum Cosmology · Physics 2016-06-27 Chao-Qiang Geng , Chung-Chi Lee

A primordial inflationary phase allows one to erase any possible anisotropic expansion thanks to the cosmic no-hair theorem. If there is no global anisotropic stress, then the anisotropic expansion rate tends to decrease. What are the…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-04 Thiago S. Pereira , Cyril Pitrou

We study the quantum evolution of the early universe, its semi-classical analogue together with inflationary regime, in view of a generalized modified theory of gravity. The action is built by supplementing the non-minimally coupled…

High Energy Physics - Theory · Physics 2021-01-11 Ranajit Mandal , Dalia Saha , Mohosin Alam , Abhik Kumar Sanyal

An earlier paper points out that a quantum treatment of the string landscape is necessary. It suggests that the wavefunction of the universe is mobile in the landscape until the universe reaches a meta-stable site with its cosmological…

High Energy Physics - Theory · Physics 2009-04-21 Qing-Guo Huang , S. -H. Henry Tye

It has been known for some time that the usual inference drawn from the observed near-flatness of the large-scale Universe - namely the existence of a cosmological "flatness problem", which is then taken as a partial, but key motivation for…

General Relativity and Quantum Cosmology · Physics 2022-04-18 Marc Holman

We connect a possible solution for the ``cosmological constant problem'' to the existence of a (postulated) conformal fixed point in a fundamental theory. The resulting cosmology leads to quintessence, where the present acceleration of the…

High Energy Physics - Theory · Physics 2009-11-07 C. Wetterich

According to the most popular scenario, the early Universe should have experienced an accelerated expansion phase, called Cosmological Inflation, after which the standard Big Bang Cosmology would have taken place giving rise to the…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 Alessandro Di Marco , Gianfranco Pradisi , Giancarlo de Gasperis , Paolo Cabella

The world view suggested by quantum cosmology is that inflating universes with all possible values of the fundamental constants are spontaneously created out of nothing. I explore the consequences of the assumption that we are a `typical'…

General Relativity and Quantum Cosmology · Physics 2010-11-01 Alexander Vilenkin

We argue that the emergent spacetime picture admits a background-independent formulation of cosmic inflation. The inflation in this picture corresponds to the dynamical emergence of spacetime while the conventional inflation is simply an…

High Energy Physics - Theory · Physics 2019-02-27 Hyun Seok Yang

Cosmological inflation and topological defects have been considered for a long time, either in disagreement or in competition. On the one hand an inflationary era is required to solve the shortcomings of the hot big bang model, while on the…

High Energy Physics - Theory · Physics 2008-11-26 Mairi Sakellariadou

The present work deals with a cosmological model having particle creation mechanism in the framework of irreversible thermodynamics. In the second order non-equilibrium thermodynamical prescription, the particle creation rate is treated as…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Subenoy Chakraborty , Supriya Pan , Subhajit Saha

Observations indicate that the universe is effectively flat, but they do not rule out a closed universe. The role of positive curvature is negligible at late times, but can be crucial in the early universe. In particular, positive curvature…

General Relativity and Quantum Cosmology · Physics 2010-04-06 George Ellis , Roy Maartens

The idea that the vacuum energy density $\rho_{\Lambda}$ could be time dependent is a most reasonable one in the expanding Universe; in fact, much more reasonable than just a rigid cosmological constant for the entire cosmic history. Being…

General Relativity and Quantum Cosmology · Physics 2015-07-08 Harald Fritzsch , Joan Sola

The cosmon field responsible for dynamical dark energy can induce an inflationary period in early cosmology. Details depend on dilatation symmetry breaking terms in its potential and kinetic term that are relevant only during early stages…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 C. Wetterich

We present a unified framework that simultaneously addresses the dynamics of early-time cosmic inflation and late-time cosmic acceleration within the context of a single scalar field non-minimally coupled to gravity. By employing an…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Seong Chan Park

We wish to demonstrate how the presence of a dynamic cosmological parameter, plus a model of the universe as a quantum computer can be combined to give us a picture of early universe inflationary physics which is quite non linear, with a…

Mathematical Physics · Physics 2011-11-10 A. W. Beckwith