Results 21 to 30 of about 3,462 (164)

A Bias-free Cosmological Analysis with Quasars Alleviating H 0 Tension

The Astrophysical Journal Supplement Series, 2023
Cosmological models and their parameters are widely debated because of theoretical and observational mismatches of the standard cosmological model, especially the current discrepancy between the value of the Hubble constant, H _0 , obtained by Type Ia ...
Aleksander Łukasz Lenart, Giada Bargiacchi, Maria Giovanna Dainotti, Shigehiro Nagataki, Salvatore Capozziello   +4 more
doaj   +1 more source

Non-singular pre-big bang scenarios from all-order α′ corrections

Journal of High Energy Physics, 2023
We reformulate in Hamiltonian language the recent proposal by Hohm and Zwiebach of an action yielding the most general O(d, d)-symmetric string cosmology equations, at tree-level in the string-loop expansion, but to all orders in the α′ expansion.
M. Gasperini, G. Veneziano
doaj   +1 more source

Remembrance of things past

Journal of High Energy Physics, 2023
Nonlinear sigma models on de Sitter background have proved a useful prototype for quantum gravity in summing the large logarithms which arise from loop corrections.
R. P. Woodard, B. Yesilyurt
doaj   +1 more source

MULTIVERSE COSMOLOGICAL MODELS

Modern Physics Letters A, 2004
Recent advances in string theory and inflationary cosmology have led to a surge of interest in the possible existence of an ensemble of cosmic regions, or "universes", among the members of which key physical parameters, such as the masses of elementary particles and the coupling constants, might assume different values.
openaire   +2 more sources

A Generalized Solution of Bianchi Type-V Models with Time-Dependent G and Λ

Universe, 2018
We study the homogeneous but anisotropic Bianchi type-V cosmological model with time-dependent gravitational and cosmological “constants”. Exact solutions of the Einstein field equations (EFEs) are presented in terms of adjustable parameters ...
Alnadhief H. A. Alfedeel, Amare Abebe, Hussam M. Gubara   +2 more
doaj   +1 more source

Post-Newtonian cosmological modelling [PDF]

Physical Review D, 2015
22 pages, 5 figures, v2: Published version, v4: Corrections to published ...
Sanghai, VAA, Clifton, T
openaire   +3 more sources

The BINGO/ABDUS Project: Forecast for Cosmological Parameters from a Mock Fast Radio Burst Survey

The Astrophysical Journal
There are various surveys that will provide excellent data to search for and localize fast radio bursts (FRBs). The BINGO project will be one such survey, and this collaboration has already estimated an FRB detection rate that the project will yield.
Xue Zhang, Yu Sang, Gabriel A. Hoerning, Filipe B. Abdalla, Elcio Abdalla, Amilcar Queiroz, André A. Costa, Ricardo G. Landim, Chang Feng, Bin Wang, Marcelo V. dos Santos, Thyrso Villela, Carlos A. Wuensche, Jiajun Zhang, Edmar C. Gurjão, Alessandro Marins, Alexandre J. R. Serres, Linfeng Xiao   +17 more
doaj   +1 more source

Building analytical three-field cosmological models

European Physical Journal C: Particles and Fields, 2018
A difficult task to deal with is the analytical treatment of models composed of three real scalar fields, as their equations of motion are in general coupled and hard to integrate. In order to overcome this problem we introduce a methodology to construct
J. R. L. Santos, P. H. R. S. Moraes, D. A. Ferreira, D. C. Vilar Neta   +3 more
doaj   +1 more source

States of low energy in the Schwinger effect

Journal of High Energy Physics, 2023
States of low energy in cosmology minimise the energy density when smeared in a chosen time interval. We extend such construction to generic homogeneous (possibly anisotropic) particle creation settings.
Álvaro Álvarez-Domínguez, Luis J. Garay, Mercedes Martín-Benito, Rita B. Neves   +3 more
doaj   +1 more source

Collapse Models and Cosmology [PDF]

, 2020
minor typo in equation (30) corrected, conclusions and results ...
Martin, Jérôme, Vennin, Vincent
openaire   +3 more sources