Results 41 to 50 of about 967 (212)
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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Cosmological Perturbations via Quantum Corrections in M-Theory
Universe, 2021 In the early universe, it is important to take into account the quantum effect of gravity to explain the feature of inflation. In this paper, we consider the M-theory effective action which consists of 11-dimensional supergravity and (Weyl)4 terms.
Kazuho Hiraga, Yoshifumi Hyakutake
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Cosmological perturbations in unimodular gravity [PDF]
Journal of Cosmology and Astroparticle Physics, 2014 We study cosmological perturbation theory within the framework of unimodular gravity. We show that the Lagrangian constraint on the determinant of the metric required by unimodular gravity leads to an extra constraint on the gauge freedom of the metric perturbations. Although the main equation of motion for the gravitational potential remains the same,
Gao, Caixia +3 more
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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 in generalised dark Lagrangians
Journal of High Energy Physics, 2018 We describe a new method to parameterise dark energy theories including massive gravity, elastic dark energy and tensor-metric theories. We first examine the existing framework which describes any second order Lagrangian which depends on the variation of
James Edholm, Jonathan Pearson
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‘Turkeys Cannot Vote for Christmas’: Why Epistemic Disobedience in an Anti‐Black World Matters
Australian Journal of Social Issues, EarlyView.ABSTRACT Never in the history of global coloniality has the idea of epistemic disobedience been as important as in the 21st century. This is not only because the struggle for decolonisation has shifted from physical confrontation between the coloniser and the colonised into a battle of ideas but also because the former has deployed the idea of ...
Morgan Ndlovu
wiley +1 more source
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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Cosmological Perturbations [PDF]
, 2002 Lecture notes. Proceedings of the 1st Aegean Summer School on Cosmology (Springer LNP).
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Relativistic Hydrodynamic Cosmological Perturbations [PDF]
General Relativity and Gravitation, 1999 16 pages, no figure, To appear in Gen.
Hwang, Jai-chang, Noh, Hyerim
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