English
Related papers

Related papers: Disentangling the Cosmic/Comoving Duality: The Cog…

200 papers

Observation indicates that the expansion of the Universe is accelerating and favours a dynamical cosmological constant, \Lambda(t). We consider the possibility that this is due to a scalar field which has undergone a very recent phase…

High Energy Physics - Phenomenology · Physics 2014-11-17 John McDonald

The future evolution of the universe suggested by the cosmological model proposed earlier at this meeting by the authors is explored. The fundamental role played by the positive "cosmological constant" is emphasized. Dyson's 1979 paper…

General Physics · Physics 2007-05-23 H. Pierre Noyes , James Lindesay

A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the coincidence and magnitude fine-tuning problems of the Cosmological Constant…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-14 Brett Bochner

The construction of quantum field theory (QFT) of a free massive scalar field with respect to a general congruence of observers is considered, the splitting into positive- and negative-frequency modes being defined by diagonalization of the…

High Energy Physics - Theory · Physics 2018-12-13 P. O. Kazinski

All measurements are comparisons. The only physically accessible degrees of freedom (DOFs) are dimensionless ratios. The objective description of the universe as a whole thus predicts only how these ratios change collectively as one of them…

General Relativity and Quantum Cosmology · Physics 2018-02-07 Tim A Koslowski , Flavio Mercati , David Sloan

We consider new cosmological solutions with a collapsing, an intermediate and an expanding phase. The boundary between the expanding (collapsing) phase and the intermediate phase is seen by comoving observers as a cosmological past (future)…

High Energy Physics - Theory · Physics 2009-11-07 L. Cornalba , Miguel S. Costa

In this paper we propose that cosmological time is a quantum observable that does not commute with other quantum operators essential for the definition of cosmological states, notably the cosmological constant. This is inspired by…

General Relativity and Quantum Cosmology · Physics 2020-02-11 Joao Magueijo , Lee Smolin

In the history of cosmology physical paradoxes played important role for development of contemporary world models. Within the modern standard cosmological model there are both observational and conceptual cosmological paradoxes which…

General Physics · Physics 2015-01-09 Yurij Baryshev

We present a theory based upon the treatment of the gravitational field as a sea of gravity quanta, as defined elsewhere. The resultant model for the Universe is a static one, like Einstein first saw, with a new feature: a local shrinking…

General Physics · Physics 2015-06-26 Antonio Alfonso-Faus

The standard big bang cosmology has been greatly successful in explaining many observational aspects of the real universe. However, two particular diffficulties faced by it are the so-called ``horizon'' and ``flatness'' problems. By…

General Physics · Physics 2007-05-23 Abhas Mitra

Some cosmological models based on the gravitational theory $f(R) = R+\zeta R^2$, and on fluids obeying to the equations of state of Redlich-Kwong, Berthelot, and Dieterici are proposed for describing smooth transitions between different…

General Relativity and Quantum Cosmology · Physics 2021-10-27 Saikat Chakraborty , Daniele Gregoris

We explore the real solutions to the Spherical Collapse Model in a non-flat Universe with a Cosmological Constant, and observe a possible situation for a fake or Ghost Collapse, in which an expanding overdense spherical region, turns around…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-26 Aditya Vidhate , Rahul Nigam

We propose that the size of the universe and its rate of expansion cannot be simultaneously specified with arbitrary precision, a quantum mechanical statement encoded in a deformed commutation relation for the scale factor. The deformation…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-15 Savvas M. Koushiappas

An oscillating, compact Friedmann universe with a massive conformally coupled scalar field is studied in the framework of quantum cosmology. The scalar field is treated as a perturbation and we look for solutions of the Wheeler-DeWitt…

General Relativity and Quantum Cosmology · Physics 2019-10-23 Thibault Damour , Alexander Vilenkin

We applied the theory of regularly varying functions to the analysis of the cosmological parameters for the $\Lambda$CDM model with the matter dominated evolution. Carroll et al. proved in 1992 that for this type of universe with the…

Mathematical Physics · Physics 2017-11-21 Žarko Mijajlović , Nadežda Pejović , Viktor Radović

Increasing improvements in the independent determinations of the Hubble constant and the age of the universe now seem to indicate that we need a small non-vanishing cosmological constant to make the two independent observations consistent…

High Energy Physics - Phenomenology · Physics 2009-10-28 Anupam Singh

A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the magnitude and coincidence fine-tuning problems of the Cosmological Constant…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-14 Brett Bochner

The current observations are usually explained by an accelerating expansion of the present universe. However, with the present quality of the supernovae Ia data, the allowed parameter space is wide enough to accommodate the decelerating…

Astrophysics · Physics 2009-11-07 R. G. Vishwakarma

We propose an alternate cosmological model in which our observable universe is an island in a cosmological constant sea. Initially the universe is filled with cosmological constant of the currently observed value but is otherwise empty. In…

Astrophysics · Physics 2009-11-10 Sourish Dutta , Tanmay Vachaspati

In the standard FRW formalism, the scale factor is assumed to describe the expansion of the universe. However, by examining empty space with a positive cosmological constant (i.e., a de Sitter space), we find that this assumption is…

General Physics · Physics 2025-08-05 J. M. Greben