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Loop quantum cosmology (LQC) provides a resolution of the classical big bang singularity in the deep Planck era. The evolution, prior to the usual slow-roll inflation, naturally generates excited states at the onset of the slow-roll…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-07 Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng

We present the results of a set of cosmological N-body simulations with standard $\Lambda$CDM cosmology but characterized by a scale-dependent primordial non-Gaussianity of the local type featuring a power-law dependence of the $f_{\rm…

In this work, we study the large scale structure formation in the modified gravity in the framework of Palatini formalism and compare the results with the equivalent smooth dark energy models as a tool to distinguish between these models.…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Shant Baghram , Sohrab Rahvar

Extremely large surveys with future experiments like Euclid and the SKA will soon allow us to access perturbation modes close to the Hubble scale, with wavenumbers $k \sim \mathcal{H}$. If a modified gravity theory is responsible for cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-03 Tessa Baker , Philip Bull

Modified gravity models with scale-dependent linear growth typically exhibit an enhancement in the power spectrum beyond a certain scale. The conventional methods for extracting cosmological information usually involve inferring modified…

Modified gravity and massive neutrino cosmologies are two of the most interesting scenarios that have been recently explored to account for possible observational deviations from the concordance $\Lambda$-cold dark matter ($\Lambda$CDM)…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-15 Jorge Enrique García-Farieta , Federico Marulli , Alfonso Veropalumbo , Lauro Moscardini , Rigoberto Casas , Carlo Giocoli , Marco Baldi

We present a systematic study of galaxy bias in the presence of primordial non-Gaussianity in General Relativity (GR) at second order in perturbation theory. The non-linearity of the Poisson equation in GR and primordial non-Gaussianity are…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Obinna Umeh , Kazuya Koyama

We use N-body simulations to study the statistics of massive halos and redshift space distortions for theories with a standard \Lambda CDM expansion history and a galileon-type scalar field. The extra scalar field increases the…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Mark Wyman , Elise Jennings , Marcos Lima

Several inflationary models predict the possibility that the primordial perturbations of the density field may contain a degree of non-Gaussianity which would influence the subsequent evolution of cosmic structures at large scales. In order…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 M. Roncarelli , L. Moscardini , E. Branchini , K. Dolag , M. Grossi , F. Iannuzzi , S. Matarrese

Since the discovery of the accelerated expansion of the Universe in 1998, modified gravity (MG) theories have attracted considerable attention as alternatives to dark energy (DE). While distinguishing the effects of MG from those of DE…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-16 Alejandro Aviles

Every theory that modifies gravity at cosmological distances and that is not already ruled out by the Solar system observations must exhibit some nonlinear mechanism that turns off the modification close to a compact matter source. Given…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-20 Karel Van Acoleyen

We present a new test of gravitational physics by comparing the growth rate of cosmic structure measured around voids with that measured around galaxies in the same large-scale structure dataset, the low-redshift 6-degree Field Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 Ixandra Achitouv , Chris Blake , Paul Carter , Jun Koda , Florian Beutler

The statistics of dark matter halos is an essential component of understanding the nonlinear evolution in modified gravity cosmology. Based on a series of modified gravity N-body simulations, we investigate the halo mass function,…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-21 Youcai Zhang , Pengjie Zhang , Xiaohu Yang , Weiguang Cui

In this investigation, we perform an observational statistical analysis in the theory of $ f(R, L_m) $ gravity. The proposed theoretical model is based on the Ricci scalar's non-linear contribution. We use a distinct parameterization for…

General Relativity and Quantum Cosmology · Physics 2024-08-30 J. K. Singh , Shaily , Akanksha Singh , Harshna Balhara , Joao R. L. Santos

We study the evolution of linear perturbations in metric f(R) models of gravity and identify a potentially observable characteristic scale-dependent pattern in the behavior of cosmological structures. While at the background level viable…

Astrophysics · Physics 2014-11-18 Levon Pogosian , Alessandra Silvestri

High-precision constraints on primordial non-Gaussianity (PNG) will significantly improve our understanding of the physics of the early universe. Among all the subtleties in using large scale structure observables to constrain PNG,…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-10 E. Di Dio , H. Perrier , R. Durrer , G. Marozzi , A. Moradinezhad Dizgah , J. Noreña , A. Riotto

Differences in masses inferred from dynamics, such as velocity dispersions or X-rays, and those inferred from lensing are a generic prediction of modified gravity theories. Viable models however must include some non-linear mechanism to…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-25 Fabian Schmidt

Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the universe. We calculate quasilinear effects in the growth of structure in f(R) models of gravity using perturbation…

Astrophysics · Physics 2009-10-29 Alex Borisov , Bhuvnesh Jain

We discuss models of primordial density perturbations where the non-Gaussianity is strongly scale-dependent. In particular, the non-Gaussianity may have a sharp cut-off and be very suppressed on large cosmological scales, but sizeable on…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-18 Antonio Riotto , Martin S. Sloth