Results 41 to 50 of about 2,969 (164)

Dark Energy and Inflation from Gravitational Waves

Universe, 2017
In this seven-part paper, we show that gravitational waves (classical and quantum) produce the accelerated de Sitter expansion at the start and at the end of the cosmological evolution of the Universe.
Leonid Marochnik
doaj   +1 more source

Does DESI DR2 Challenge ΛCDM Paradigm?

The Astrophysical Journal
Although the debate about the systematic errors of DESI DR1 is still open, recent DESI DR2 is consistent with DESI DR1 and further strengthens the results of DESI DR1.
Himanshu Chaudhary, Salvatore Capozziello, Vipin Kumar Sharma, Ghulam Mustafa   +3 more
doaj   +1 more source

Spacetime Foam, Midisuperspace, and the Cosmological Constant

Universe, 2021
Perhaps the cosmological constant really is huge at the Planck scale, but is “hidden” by Planck scale quantum fluctuations of spacetime. I briefly review this proposal and provide some evidence, coming from a simplified midisuperspace model, that an ...
Steven Carlip
doaj   +1 more source

Evolution of Cosmological Perturbations in a Brane-Universe [PDF]

Physical Review Letters, 2001
Physical Review ...
openaire   +4 more sources

Does cosmological evolution select for technology?

New Journal of Physics, 2020
If the parameters defining the physics of our universe departed from their present values, the observed rich structure and complexity would not be supported. This article considers whether similar fine-tuning of parameters applies to technology.
Jeffrey M Shainline
doaj   +1 more source

Stochastic inflation from quantum field theory and the parametric dependence of the effective noise amplitude

Journal of High Energy Physics, 2022
The non-linear dynamics of long-wavelength cosmological fluctuations may be phrased in terms of an effective classical, but stochastic evolution equation.
Jens O. Andersen, Magdalena Eriksson, Anders Tranberg   +2 more
doaj   +1 more source

Expansion Collapse Theory of Cosmological Evolution

Journal of Harbin University of Science and Technology, 2017
In the big bang theory，many key puzzles have not been solved． This paper presents an expansion collapse theory of cosmological evolution that the universe originated from the big bang，expanding at beginning， then contracting，and finally collapsing to ...
ZHANG Shao-yong
doaj   +1 more source

On the gravitational instability in the Newtonian limit of MOG

Physics Letters B, 2017
We have found some analytical cosmological solutions to MOdified Gravity (MOG). These solutions describe different evolutionary epochs of an isotropic and homogeneous universe.
Fatimah Shojai, Samira Cheraghchi, Hamed Bouzari Nezhad   +2 more
doaj   +1 more source

Modified gravity with an exponential function of curvature

European Physical Journal C: Particles and Fields, 2020
The role of an exponential function of the scalar curvature in the modified gravity is analyzed. Two models are proposed. A toy model that complies with local and cosmological constraints and gives appropriate qualitative description of the cosmic ...
L. N. Granda
doaj   +1 more source

General anisotropic cosmological solutions and physical viability in f(T, B) gravity

European Physical Journal C: Particles and Fields
An anisotropic Bianchi type-I cosmological model is examined in the framework of modified teleparallel gravity described by a general function f(T, B) of the torsion scalar and the boundary term.
Arshad Ali, Fiaz Hussain
doaj   +1 more source