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We report a technique to calculate the impact of distinct physical processes inducing non-Gaussianity on the cosmological density field. A natural decomposition of the cosmic genus statistic into an orthogonal polynomial sequence allows…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-07 J. Berian James

We calculate the bispectrum, B_g(k_1,k_2,k_3), Fourier transform of the three-point function of density peaks (e.g., galaxies), using two different methods: the Matarrese-Lucchin-Bonometto formula and the locality of galaxy bias. The…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-28 Donghui Jeong , Eiichiro Komatsu

Scalar metric fluctuations generically source a spectrum of gravitational waves at second order in perturbation theory, poising gravitational wave experiments as potentially powerful probes of the small-scale curvature power spectrum. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-20 Peter Adshead , Kaloian D. Lozanov , Zachary J. Weiner

Based on the relationship between thermodynamics and gravity we propose, with the aid of Verlinde's formalism, an alternative interpretation of the dynamical evolution of the Friedmann-Robertson-Walker Universe. This description takes into…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Rafael C. Nunes , Edésio M. Barboza , Everton M. C. Abreu , Jorge Ananias Neto

We examine the effective theory of single-field inflation in the limit where the scalar perturbations propagate with a small speed of sound. In this case the non-linearly realized time-translation symmetry of the Lagrangian implies large…

High Energy Physics - Theory · Physics 2015-05-27 Daniel Baumann , Daniel Green

In a fully inhomogeneous, anisotropic cosmological simulation performed by solving Einstein's equations with numerical relativity, we find a local measurement of the effective Hubble parameter differs by less than 1\% compared to the global…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-10 Hayley J. Macpherson , Paul D. Lasky , Daniel J. Price

When dealing with observables, one needs to generalize the bias relation between the observed galaxy fluctuation field to the underlying matter distribution in a gauge-invariant way. We provide such relation at second-order in perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-20 N. Bartolo , S. Matarrese , A. Riotto

Local primordial non-Gaussianity (LPNG) couples long-wavelength cosmological fluctuations to the short-wavelength behavior of galaxies. This coupling is encoded in bias parameters including $b_{\phi}$ and $b_{\delta\phi}$ at linear and…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-11 James M. Sullivan , Shi-Fan Chen

We study gravitational waves (GWs) induced by non-Gaussian curvature perturbations. We calculate the density parameter per logarithmic frequency interval, $\Omega_\text{GW}(k)$, given that the power spectrum of the curvature perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-29 Rong-gen Cai , Shi Pi , Misao Sasaki

We develop a possibility of generating tensor non-Gaussianity in a kind of anisotropic inflation, where a $U(1)$ gauge field is kinetically coupled to a spectator scalar field. Owing to this coupling, the coherent mode of the electric field…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-31 Takashi Hiramatsu , Kai Murai , Ippei Obata , Shuichiro Yokoyama

In this paper, we introduce the topological persistence diagram as a statistic for Cosmic Microwave Background (CMB) temperature anisotropy maps. A central concept in `Topological Data Analysis' (TDA), the idea of persistence is to…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-28 Alex Cole , Gary Shiu

We study a non local approximation of the Gaussian perimeter, proving the Gamma convergence to the local one. Surprisingly, in contrast with the local setting, the halfspace turns out to be a volume constrained stationary point if and only…

Analysis of PDEs · Mathematics 2020-11-17 Antonio De Rosa , Domenico Angelo La Manna

Correlated adiabatic and isocurvature perturbation modes are produced during inflation through an oscillation mechanism when extra scalar degrees of freedom other than the inflaton field are present. We show that this correlation…

High Energy Physics - Phenomenology · Physics 2009-11-07 N. Bartolo , S. Matarrese , A. Riotto

We investigate the effect of primordial non-Gaussianities on halo number counts using N-body simulations with different values of $f_{\rm NL}^{\rm loc}$. We show how current theoretical models fail to adequately describe the non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-30 Luca Fiorino , Sofia Contarini , Federico Marulli , Ariel G. Sanchez , Marco Baldi , Andrea Fiorilli , Lauro Moscardini

We study the formation of primordial black holes when they are generated by the collapse of large overdensities in the early universe. Since the density contrast is related to the comoving curvature perturbation by a nonlinear relation, the…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-01 V. De Luca , G. Franciolini , A. Kehagias , M. Peloso , A. Riotto , C. Ünal

The primordial non-Gaussianity parameters fNL and tauNL may be scale-dependent. We investigate the capability of future measurements of the CMB mu-distortion, which is very sensitive to small scales, and of the large-scale halo bias to test…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-27 Matteo Biagetti , Hideki Perrier , Antonio Riotto , Vincent Desjacques

We compute in detail how deviations from Einstein gravity at the inflation energy scale could appear as non-Gaussian features in the sky. To illustrate this we use multi-field $\alpha-$attractor models in the framework of supergravity to…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-14 Nicola Bartolo , Domenico Matteo Bianco , Raul Jimenez , Sabino Matarrese , Licia Verde

We present measurements of the bispectrum of dark matter halos in numerical simulations with non-Gaussian initial conditions of the local type. We show, in the first place, that the overall effect of primordial non-Gaussianity on the halo…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Emiliano Sefusatti , Martin Crocce , Vincent Desjacques

In this paper we examine how primordial non-Gaussianity contributes to nonlinear perturbative orders in the expansion of the density field at large scales in the matter dominated era. General Relativity is an intrinsically nonlinear theory,…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-27 Hedda Alice Gressel , Marco Bruni

Many traditional algorithms applied in gravitational-wave astronomy rely on the assumption of Gaussian noise, a condition not always met. To meet this need, this study extends a robust statistical framework, advancing previous work on…

General Relativity and Quantum Cosmology · Physics 2026-02-26 Argyro Sasli , Minas Karamanis , Nikolaos Karnesis , Michael W. Coughlin , Vuk Mandic , Uroš Seljak , Nikolaos Stergioulas
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