Zobrazeno 1 - 10
of 304
pro vyhledávání: '"Dunsby, Peter"'
Over the last decade, much attention has been given to the study of modified gravity theories to find a more natural explanation for the late-time acceleration of the Universe. Particular attention has focused on the so-called $f(R)$ dark energy mode
Externí odkaz:
http://arxiv.org/abs/2408.03998
Publikováno v:
Phys. Rev. D 110, 043505 (2024)
We perform a detailed dynamical system analysis for the behaviour of a Dirac-Born-Infeld (DBI) field in a spatially closed Friedmann-Lema\^itre-Robertson-Walker (FLRW) cosmology. The DBI field is characterised by a potential and brane tension. We stu
Externí odkaz:
http://arxiv.org/abs/2405.06031
We study the causal dynamics of an embedded null horizon foliated by marginally outer trapped surfaces (MOTS) for a locally rotationally symmetric background spacetime subjected to linear perturbations. We introduce a simple procedure which character
Externí odkaz:
http://arxiv.org/abs/2404.14742
We present a dynamical system formulation for inhomogeneous LRS-II spacetimes using the covariant 1+1+2 decomposition approach. Our approach describes the LRS-II dynamics from the point of view of a comoving observer. Promoting the covariant radial d
Externí odkaz:
http://arxiv.org/abs/2404.01161
We consider a double polytropic cosmological fluid and demonstrate that, when one constituent resembles a bare cosmological constant while the other emulates a generalized Chaplygin gas, a good description of the Universe's large-scale dynamics is ob
Externí odkaz:
http://arxiv.org/abs/2403.17880
We present a covariant description of non-vacuum static spherically symmetric spacetimes in $f(R)$ gravity applying the (1+1+2) covariant formalism. The propagation equations are then used to derive a covariant and dimensionless form of the Tolman-Op
Externí odkaz:
http://arxiv.org/abs/2403.00070
We study the existence of gradient conformal Killing vectors (CKVs) in the class of locally rotationally symmetric (LRS) spacetimes which generalizes spherically symmetric spacetimes, and investigate some implications for the evolutionary character o
Externí odkaz:
http://arxiv.org/abs/2401.07605
We explore a generalised unified dark energy model that incorporates a non-minimal interaction between a tachyonic fluid and an additional scalar field. Specifically, we require that the second field possesses a vacuum energy, introducing an inelimin
Externí odkaz:
http://arxiv.org/abs/2308.15776
Publikováno v:
JCAP06(2023)030
Non-singular bouncing cosmologies are well--motivated models for the early universe. Recent observational data are consistent with positive spatial curvature and allow for a natural collapsing and bouncing phase in the very early universe. Additional
Externí odkaz:
http://arxiv.org/abs/2212.01093
Publikováno v:
Mon.Not.Roy.Astron.Soc. 518 (2022) 4, 6102-6113
f(R) gravity is one of the simplest viable modifications to General Relativity: it passes local astrophysical tests, predicts both the early-time cosmic inflation and the late-time cosmic acceleration, and also describes dark matter. In this paper, w
Externí odkaz:
http://arxiv.org/abs/2210.09303