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We first derive the primordial power spectra, spectral indices and runnings of both scalar and tensor perturbations of a flat inflationary universe to the second-order approximations of the slow-roll parameters, in the framework of loop…

General Relativity and Quantum Cosmology · Physics 2016-03-25 Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng , Qiang Wu

We compute the connected four point correlation function (the trispectrum in Fourier space) of cosmological density perturbations at one-loop order in Standard Perturbation Theory (SPT) and the Effective Field Theory of Large Scale…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-06 Daniele Bertolini , Katelin Schutz , Mikhail P. Solon , Kathryn M. Zurek

We compare the non-linear matter power spectrum in real space calculated analytically from 3rd-order perturbation theory with N-body simulations at 1<z<6. We find that the perturbation theory prediction agrees with the simulations to better…

Astrophysics · Physics 2010-11-11 Donghui Jeong , Eiichiro Komatsu

General and explicit predictions from the integrated perturbation theory (iPT) for power spectra and correlation functions of biased tracers are derived and presented in the one-loop approximation. The iPT is a general framework of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-05 Takahiko Matsubara

We examine the effects of the linear and the cosmological redshift-space distortions on the power spectrum of cosmological objects on a light cone. We develop theoretical formulae for the power spectrum in linear theory of density…

Astrophysics · Physics 2009-10-31 Hiroaki Nishioka , Kazuhiro Yamamoto

We apply the effective field theory approach to the coupled metric-inflaton system, in order to investigate the impact of higher dimension operators on the spectrum of scalar and tensor perturbations in the short-wavelength regime. In both…

High Energy Physics - Theory · Physics 2009-09-28 Cristian Armendariz-Picon , Michele Fontanini , Riccardo Penco , Mark Trodden

Recently a number of analytic prescriptions for computing the non-linear matter power spectrum have appeared in the literature. These typically involve resummation or closure prescriptions which do not have a rigorous error control, thus…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Jordan Carlson , Martin White , Nikhil Padmanabhan

The next generation of telescopes will usher in an era of precision cosmology, capable of determining the cosmological model to beyond the percent level. For this to be effective, the theoretical model must be understood to at least the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Obinna Umeh , Chris Clarkson , Roy Maartens

Perturbation theory (PT) is often used to model statistical observables capturing the translation and rotation-invariant information in cosmological density fields. PT produces higher-order corrections by integration over linear statistics…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-07 Zachary Slepian

We find several missing one-loop-order contributions in previous considerations about secondary gravitational waves induced at nonlinear order in cosmological perturbations. We consider a consistent perturbative expansion to third-order in…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-03 Chao Chen , Atsuhisa Ota , Hui-Yu Zhu , Yuhang Zhu

An efficient technique for computing perturbation power spectra in field ordering theories of cosmic structure formation is introduced, enabling computations to be carried out with unprecedented precision. Large scale simulations are used…

Astrophysics · Physics 2009-07-09 Ue-Li Pen , Uros Seljak , Neil Turok

We propose and construct a two-parameter perturbative expansion around a Friedmann-Lema\^{i}tre-Robertson-Walker geometry that can be used to model high-order gravitational effects in the presence of non-linear structure. This framework…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Sophia R. Goldberg , Timothy Clifton , Karim A. Malik

We present a new method for calculating loops in cosmological perturbation theory. This method is based on approximating a $\Lambda$CDM-like cosmology as a finite sum of complex power-law universes. The decomposition is naturally achieved…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-25 Marko Simonović , Tobias Baldauf , Matias Zaldarriaga , John Joseph Carrasco , Juna A. Kollmeier

Modeling the large-scale structure of the universe on nonlinear scales has the potential to substantially increase the science return of upcoming surveys by increasing the number of modes available for model comparisons. One way to achieve…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-30 Marcel Schmittfull , Zvonimir Vlah

Loop quantum cosmology tries to capture the main ideas of loop quantum gravity and to apply them to the Universe as a whole. Two main approaches within this framework have been considered to date for the study of cosmological perturbations:…

General Relativity and Quantum Cosmology · Physics 2015-10-08 B. Bolliet , J. Grain , C. Stahl , L. Linsefors , A. Barrau

The full set of cosmological observables coming from linear scalar and tensor perturbations of loop quantum cosmology is computed in the presence of inverse-volume corrections. Background inflationary solutions are found at linear order in…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Martin Bojowald , Gianluca Calcagni

The corrections to the cosmological models induced by non-minimal coupling between scalar field and torsion are considered. To determine these corrections in explicit form, the power-law parametrization of these corrections are proposed.…

General Relativity and Quantum Cosmology · Physics 2025-03-25 I. V. Fomin , S. V. Chervon , L. K. Duchaniya , B. Mishra

The two-point function for tensor metric perturbations around de Sitter spacetime including one-loop corrections from massless conformally coupled scalar fields is calculated exactly. We work in the Poincar\'e patch (with spatially flat…

General Relativity and Quantum Cosmology · Physics 2012-09-06 Markus B. Fröb , Albert Roura , Enric Verdaguer

This chapter provides a review of the frameworks developed for cosmological perturbation theory in loop quantum cosmology, and applications to various models of the early universe including inflation, ekpyrosis and the matter bounce, with…

General Relativity and Quantum Cosmology · Physics 2024-03-08 Ivan Agullo , Anzhong Wang , Edward Wilson-Ewing

Loop corrections to the power spectrum are frequently computed using approximate non-linear kernels adopted from an Einstein de-Sitter (EdS) cosmology. We present an algorithm that allows us to take the full time- and scale-dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-04 Mathias Garny , Petter Taule