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The existence of a thermodynamic arrow of time in the present universe implies that the initial state of the observable portion of our universe at (or near) the ``big bang'' must have been very ``special''. We argue that it is not plausible…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Robert M. Wald

Recently, the notion that the number of vacua is enormous has received increased attentions, which may be regarded as a possible anthropical explanation to incredible small cosmological constant. Further, a dynamical mechanisms to implement…

High Energy Physics - Theory · Physics 2009-11-10 Yun-Song Piao

The recognition that the cosmological constant may be non-zero forces us to re-evaluate standard notions about the connection between geometry and the fate of our Universe. An open Universe can recollapse, and a closed Universe can expand…

Astrophysics · Physics 2014-10-13 Lawrence M. Krauss , Michael S. Turner

The no-boundary proposal provides a compelling theory for the initial conditions of our universe. We study the implications of such initial conditions for ekpyrotic and cyclic cosmologies. These cosmologies allow for the existence of a new…

High Energy Physics - Theory · Physics 2015-06-22 Lorenzo Battarra , Jean-Luc Lehners

Inflationary models, especially those with plateau-type potentials, are consistent with the cosmological data, but inflation itself does not resolve the initial singularity. This singularity is resolved, for example, by the idea of the…

General Relativity and Quantum Cosmology · Physics 2024-05-16 Hiroki Matsui , Alexandros Papageorgiou , Fuminobu Takahashi , Takahiro Terada

The purpose of this paper is to elucidate, by means of concepts and theorems drawn from mathematical logic, the conditions under which the existence of a multiverse is a logical necessity in mathematical physics, and the implications of…

General Physics · Physics 2014-11-20 Gordon McCabe

We propose that the Universe created from "nothing" with relatively small particles number and quickly relaxed to quasiequilibrium state at the Planck parameters. The classic cosmological solution for this Universe with Lambda-term has two…

General Relativity and Quantum Cosmology · Physics 2009-12-30 V. Burdyuzha , O. Lalakulich , Yu. Ponomarev , G. Vereshkov

In this paper we present an informal description of the Cyclic Inflation scenario which allows our universe to "start" with a negative potential energy, inflate, and then gracefully exit to a positive potential energy universe. We discuss…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-06 Tirthabir Biswas , Tomi Koivisto , Anupam Mazumdar

Recent astronomical observations of distant supernovae light-curves suggest that the expansion of the universe has recently begun to accelerate. Acceleration is created by an anti-gravitational repulsive stress, like that produced by a…

Astrophysics · Physics 2009-10-31 John Barrow , Rachel Bean , Joao Magueijo

Suspicions that the world might be some sort of a machine or algorithm existing ``in the mind'' of some symbolic number cruncher have lingered from antiquity. Although popular at times, the most radical forms of this idea never reached…

General Physics · Physics 2007-05-23 Karl Svozil

The purpose of this paper is to discuss the various types of physical universe which could exist according to modern mathematical physics. The paper begins with an introduction that approaches the question from the viewpoint of ontic…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Gordon McCabe

In this short paper, we conjecture a correspondence between the creation of the universe in entangled pairs and eternal black holes. We shall see that this correspondence will restore the matter-antimatter asymmetry at the beginning of the…

General Physics · Physics 2022-11-01 Walid Al Hajj , S. Morteza Hosseini

In physical theories, boundary or initial conditions play the role of selecting special situations which can be described by a theory with its general laws. Cosmology has long been suspected to be different in that its fundamental theory…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Martin Bojowald

An introductory account is given of the modern understanding of the physics of the early Universe. Particular emphasis is placed on the paradigm of cosmological inflation, which postulates a period of accelerated expansion during the…

Astrophysics · Physics 2008-02-03 Andrew R Liddle

Complete cosmic evolution is a popular model in cosmology. But the possibility of other different cosmic evolution model can not be negated. The nonsingular bouncing scenario models are now found in literature. This work is a representation…

General Relativity and Quantum Cosmology · Physics 2022-05-23 Subhayan Maity

In this paper we work out a multiverse scenario whose physical characteristics enable us to advance the following the conjecture that whereas the physics of particles and fields is confined to live in the realm of the whole multiverse…

Astrophysics · Physics 2014-11-18 Pedro F. Gonzalez-Diaz , Prado Martin-Moruno , Artyom V. Yurov

A more clear-cut answer to the title question is, ``Yes'' if the universal expansion started with a big bang; ``No'' if it started infinitely slowly.

Astrophysics · Physics 2009-11-07 T. Kiang

In this letter, we argue that the past of the Universe, extrapolated from standard physics and measured cosmological parameters, might be a non-singular bounce. We also show that, in this framework, quite stringent constraints can be put on…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Aurélien Barrau

The Einstein static universe has played a central role in a number of emergent scenarios recently put forward to deal with the singular origin of the standard cosmological model. Here we study the existence and stability of the Einstein…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-01 Saulo Carneiro , Reza Tavakol

The theory of the inflationary multiverse changes the way we think about our place in the world. According to its most popular version, our world may consist of infinitely many exponentially large parts, exhibiting different sets of…

High Energy Physics - Theory · Physics 2024-06-19 Andrei Linde
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