Results 51 to 60 of about 299,841 (224)
ASYMPTOTICS OF LINEARIZED COSMOLOGICAL PERTURBATIONS [PDF]
Journal of Hyperbolic Differential Equations, 2010 In cosmology an important role is played by homogeneous and isotropic solutions of the Einstein–Euler equations and linearized perturbations of these. This paper proves results on the asymptotic behavior of scalar perturbations both in the approach to the initial singularity of the background model and at late times. The main equation of interest is a
Allen, P., Rendall, A.
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Non-minimal coupling influence on the deviation from de Sitter cosmological expansion
European Physical Journal C: Particles and Fields, 2018 We investigate the models of cosmological inflation in generalized scalar–tensor gravity, which we consider as a source of deviation from de Sitter dynamics in the case of GR.
I. V. Fomin, S. V. Chervon
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Nonconservative unimodular gravity: a viable cosmological scenario?
European Physical Journal C: Particles and Fields, 2022 In this work we review the issue of imposing the conservation of the energy–momentum tensor as a necessary condition to recover the equivalence between the unimodular gravity and General Relativity (GR) equipped with a cosmological constant.
Júlio C. Fabris +3 more
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Cosmological Perturbations [PDF]
, 2002 Lecture notes. Proceedings of the 1st Aegean Summer School on Cosmology (Springer LNP).
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Journal of Quaternary Science, EarlyView.ABSTRACT Glaciokarst landscapes pose distinctive challenges for cosmogenic dating because meltwater and runoff can be rapidly rerouted into ponors and conduit networks, weakening glacier–river coupling and promoting local sediment storage. We reconstruct glacier retreat and postglacial stabilization on the Snežnik Plateau (SW Slovenia) using in situ ...
Onur Altınay +6 more
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Appearances are deceptive: can graviton have a mass?
Journal of High Energy PhysicsWe study the dynamics of linear gravitational perturbations on cosmological backgrounds of massive fermionic fields. We observe that, when gravitational and matter action are expanded to quadratic order in gravitational perturbations on cosmological ...
Leihua Liu, Tomislav Prokopec
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Scalar perturbations in cosmological f(R) models: the cosmic screening approach
European Physical Journal C: Particles and Fields, 2018 We investigate cosmological perturbations for nonlinear f(R) models within the cosmic screening approach. Matter is considered both in the form of a set of discrete point-like massive bodies and in the form of a continuous pressureless perfect fluid.
Özgür Akarsu +4 more
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Generating cosmological perturbations in non-singular Horndeski cosmologies
Journal of High Energy Physics, 2023 We construct a concrete model of Horndeski bounce with strong gravity in the past. Within this model we show that the correct spectra of cosmological perturbations may be generated at early contracting epoch, with mild fine-tuning ensuring that the ...
Yulia Ageeva +2 more
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Cosmological perturbations on the phantom brane [PDF]
Journal of Cosmology and Astroparticle Physics, 2016 We obtain a closed system of equations for scalar perturbations in a multi-component braneworld. Our braneworld possesses a phantom-like equation of state at late times, $w_{\rm eff} < -1$, but no big-rip future singularity. In addition to matter and radiation, the braneworld possesses a new effective degree of freedom - the 'Weyl fluid' or 'dark ...
Bag, Satadru +3 more
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Journal of Quaternary Science, EarlyView.ABSTRACT The Cadí Massif (42°17′09″ N, 1°38′11″ E; 2649 m a.s.l.) in the southeastern Pyrenees preserves clear evidence of Late Pleistocene glaciation, although previous research has focused almost exclusively on its northern slope. By contrast, the southern slope has remained largely unexplored.
M. Oliva +5 more
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