Results 31 to 40 of about 60,199 (278)
Coarse-grained cosmological perturbation theory [PDF]
Journal of Cosmology and Astroparticle Physics, 2012 Semi-analytical methods, based on Eulerian perturbation theory, are a promising tool to follow the time evolution of cosmological perturbations at small redshifts and at mildly nonlinear scales. All these schemes are based on two approximations: the existence of a smoothing scale and the single-stream approximation, where velocity dispersion of the ...
Pietroni, Massimo +3 more
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Cosmological perturbations and dynamical analysis for interacting quintessence
European Physical Journal C: Particles and Fields, 2019 We present the dynamical analysis for interacting quintessence, considering linear cosmological perturbations. Matter perturbations improve the background analysis and viable critical points describing the transition of the three cosmological eras are ...
Ricardo G. Landim
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Black hole perturbation theory and multiple polylogarithms
Journal of High Energy Physics, 2023 We study black hole linear perturbation theory in a four-dimensional Schwarzschild (anti) de Sitter background. When dealing with a positive cosmological constant, the corresponding spectral problem is solved systematically via the Nekrasov-Shatashvili ...
Gleb Aminov +4 more
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COSMOLOGICAL PERTURBATIONS IN PRESENCE OF SCALAR FIELDS
Odessa Astronomical Publications, 2014 We investigate the role of the scalar field assuming its presence at late stages of the Universe evolution together with dust presented by a system of an arbitrary number of gravitating masses (galaxies, groups of galaxies and clusters of galaxies) and ...
A. Yu. Burgazli, M. Eingorn, A. Zhuk
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Cosmological perturbations from stochastic gravity [PDF]
, 2008 In inflationary cosmological models driven by an inflaton field the origin of the primordial inhomogeneities which are responsible for large scale structure formation are the quantum fluctuations of the inflaton field.
A. A. Starobinsky +18 more
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Cosmological perturbations engendered by discrete relativistic species
European Physical Journal C: Particles and Fields, 2023 Within the extension of the $$\varLambda $$ Λ CDM model, allowing for the presence of neutrinos or warm dark matter, we develop the analytical cosmological perturbation theory.
Maksym Brilenkov +2 more
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Cosmological Perturbations in Bouncing Cosmologies and the Case of the Pre-Big Bang Scenario
Universe, 2022 Pre-Big Bang cosmology inspired generations of cosmologists in attempts to cure the initial Big Bang singularity using a fundamental length scale as proposed by string theory.
Valerio Bozza
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Matching conditions for cosmological perturbations [PDF]
Physical Review D, 1995 We derive the matching conditions for cosmological perturbations in a Friedmann Universe where the equation of state undergoes a sharp jump, for instance as a result of a phase transition. The physics of the transition which is needed to follow the fate of the perturbations is clarified.
Deruelle, Nathalie, Mukhanov, V. F.
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Cosmological Perturbation Theory [PDF]
Progress of Theoretical Physics Supplement, 1984 The linear perturbation theory of spatially homogeneous and isotropic universes is reviewed and reformulated extensively. In the first half of the article, a gauge-invariant formulation of the theory is carried out with special attention paid to the geometrical meaning of the perturbation.
Hideo Kodama, Misao Sasaki
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Cosmological perturbations without inflation [PDF]
Classical and Quantum Gravity, 2016 A particularly attractive feature of inflation is that quantum fluctuations inthe inflaton field may have seeded inhomogeneities in the cosmic microwavebackground (CMB) and the formation of large-scale structure. In this paper,we demonstrate that a scalar field with zero active mass, i.e., with anequation of state $\rho+3p=0$, where $\rho$ and $p$ are ...
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