Exact non-linear equations for cosmological perturbations
نویسندگان
چکیده
منابع مشابه
Evolution Equation for Non-linear Cosmological Perturbations
We present a novel approach, based entirely on the gravitational potential, for studying the evolution of non-linear cosmological matter perturbations. Starting from the perturbed Einstein equations, we integrate out the non-relativistic degrees of freedom of the cosmic fluid and obtain a single closed equation for the gravitational potential. We then verify the validity of the new equation by ...
متن کاملCosmological Perturbations: Entering the Non-Linear Regime
We consider one-loop corrections (non-linear corrections beyond leading order) to the bispectrum and skewness of cosmological density fluctuations induced by gravitational evolution, focusing on the case of Gaussian initial conditions and scale-free initial power spectra, P (k) ∝ k. As has been established by comparison with numerical simulations, tree-level (leading order) perturbation theory ...
متن کاملNon–Linear Evolution of Cosmological Perturbations
In these lecture notes I review the theory of the non–linear evolution of cosmological perturbations in a self–gravitating collisionless medium, with vanishing vorticity. The problem is first analyzed in the context of the Newtonian approximation, where the basic properties of the Zel’dovich, frozen–flow and adhesion algorithms are introduced. An exact general relativistic formalism is then pre...
متن کاملNew exact solutions for inflationary cosmological perturbations
From a general ansatz for the effective potential of cosmological perturbations we find new, exact solutions in single-scalar-field inflation: A three parameter family of exact solutions that encompasses all exact solutions that have been known previously (power-law inflation, Easther’s model, and a generalized version of Starobinsky’s solution). The main feature of this new family is that the ...
متن کاملMethod of comparison equations for cosmological perturbations
We apply the method of comparison equations to study cosmological perturbations during inflation, obtaining the full power spectra of scalar and tensor perturbations to first and to second order in the slow-roll parameters. We compare our results with those derived by means of other methods, in particular the Green’s function method and the improved WKB approximation, and find agreement for the...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Cosmology and Astroparticle Physics
سال: 2017
ISSN: 1475-7516
DOI: 10.1088/1475-7516/2017/10/027