Results 81 to 90 of about 6,154 (134)
Emergence of space and the general dynamic equation of the Friedmann-Robertson-Walker universe [PDF]
, 2013 A novel idea\char22{}that the cosmic acceleration can be understood from the perspective that spacetime dynamics is an emergent phenomenon\char22{}was proposed by T. Padmanabhan.
Wen-Yuan Ai +3 more
semanticscholar +1 more source
Gravastar Model in Krori–Barua Metric Under f(Q)$f(\mathcal {Q})$ Gravity
Fortschritte der Physik, Volume 72, Issue 7-8, August 2024.Abstract In this paper, the characteristics of a gravastar in f(Q)$f(\mathcal {Q})$ gravity, which is upheld by Krori–Barua (KB) metric are explored. The authors have used KB metric for the interior and shell regions of the gravastar. The field equations are deduced by using KB metric.
Debasmita Mohanty, Pradyumn K. Sahoo
wiley +1 more source
Einstein-Grisaru-Zanon gravity
Physics Letters BThe leading (α′)3-correction to the gravitational low-energy effective action of closed (type II) superstring theory in four-spacetime dimensions defines the Einstein-Grisaru-Zanon gravity action that is applied for a calculation of the leading ...
Ruben Campos Delgado, Sergei V. Ketov
doaj +1 more source
Unified first law and some general prescription: a redefinition of surface gravity
European Physical Journal C: Particles and Fields, 2017 The paper contains an extensive study of the unified first law (UFL) in the Friedmann–Robertson–Walker spacetime model. By projecting the UFL along the Kodama vector the second Friedmann equation can be obtained.
Sourav Haldar +2 more
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European Physical Journal C: Particles and Fields, 2023 Horizon thermodynamics is expected to be related to the effective energy based on the energy density calculated from the Friedmann equation for a Friedmann–Robertson–Walker (FRW) universe.
Nobuyoshi Komatsu
doaj +1 more source
Astronomische Nachrichten, Volume 345, Issue 2-3, February-March 2024.Abstract This paper focuses on the implications of a commutative formulation that integrates branch‐cutting cosmology, the Wheeler–DeWitt equation, and Hořava–Lifshitz quantum gravity. Building on a mini‐superspace structure, we explore the impact of an inflaton‐type scalar field on the wave function of the Universe.
Fridolin Weber +8 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
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
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
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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