Results 81 to 90 of about 11,605 (193)
The evolution of a spatially homogeneous and isotropic universe filled with a collisionless gas
, 2014 We review the evolution of a spatially homogeneous and isotropic universe described by a Friedmann-Robertson-Walker spacetime filled with a collisionless, neutral, simple, massive gas.
Astorga, Francisco +2 more
core +1 more source
Cosmology of Metric‐Affine R+βR2$R + \beta R^2$ Gravity with Pure Shear Hypermomentum
Fortschritte der Physik, Volume 72, Issue 1, January 2024.Abstract In this paper, cosmological aspects of metric‐affine f(R)$f(R)$ gravity with hyperfluid are studied. The equations of motion of the theory are obtained by varying the action with respect to the metric and the independent connection. Subsequently, considering a Friedmann‐Lemaître‐Robertson‐Walker background, the modified Friedmann equations in ...
Damianos Iosifidis +2 more
wiley +1 more source
Geometric Classifications of Perfect Fluid Space‐Time Admit Conformal Ricci‐Bourguignon Solitons
Journal of Mathematics, Volume 2024, Issue 1, 2024.This paper is dedicated to the study of the geometric composition of a perfect fluid space‐time with a conformal Ricci‐Bourguignon soliton, which is the extended version of the soliton to the Ricci‐Bourguignon flow. Here, we have delineated the conditions for conformal Ricci‐Bourguignon soliton to be expanding, steady, or shrinking.
Noura Alhouiti +6 more
wiley +1 more source
Dynamics of Einstein–Aether scalar field cosmology
European Physical Journal C: Particles and Fields, 2019 We study the cosmological evolution of the field equations in the context of Einstein–Aether cosmology by including a scalar field in a spatially flat Friedmann–Lemaître–Robertson–Walker spacetime.
Andronikos Paliathanasis +3 more
doaj +1 more source
Dissipation of oscillating scalar backgrounds in an FLRW universe
Journal of High Energy Physics, 2022 We study the dissipation of oscillating scalar backgrounds in a spatially flat Friedmann-Lemaître-Robertson-Walker universe using non-equilibrium quantum field theory.
Zi-Liang Wang, Wen-Yuan Ai
doaj +1 more source
, 2014 We exploit the parallel between dynamical black holes and cosmological spacetimes to describe the evolution of Friedmann-Lema\^itre-Robertson-Walker universes from the point of view of an observer in terms of the dynamics of the apparent horizon.
Binétruy, Pierre, Helou, Alexis
core +3 more sources
Systematic Dynamical Analysis in Palatini f(R) Gravity
Advances in Astronomy, Volume 2024, Issue 1, 2024.This paper aims to explore the evolution of the universe in the background of Palatini f(R) gravity. Considering Amendola Gannouji Polarski Tsujikawa (AGPT) f(R) gravity model, we perform a dynamical system analysis within the FLRW universe in order to analyze the impacts of this gravity model on large‐scale structure and dynamics of universe. With the
Fizza Saeed +3 more
wiley +1 more source
Correspondence between dark energy quantum cosmology and Maxwell equations
European Physical Journal C: Particles and Fields, 2019 A Friedmann–Robertson–Walker cosmology with dark energy can be modelled using a quintessence field. That system is equivalent to a relativistic particle moving on a two-dimensional conformal spacetime.
Felipe A. Asenjo, Sergio A. Hojman
doaj +1 more source
Inflation and Acceleration of the Universe by Nonlinear Magnetic Monopole Fields
, 2017 Despite impressive phenomenological successes, cosmological models are incomplete without an understanding of what happened at the big bang singularity.
Övgün, A.
core +1 more source
Generalized holographic cosmology: low-redshift observational constraint
Journal of High Energy Physics, 2021 Four-dimensional cosmological models are studied on a boundary of a five-dimensional Anti-de Sitter (AdS 5) black hole with AdS Reissner-Nordström and scalar charged Reissner-Nordström black hole solutions, where we call the former a “Hairless” black ...
Sunly Khimphun +2 more
doaj +1 more source