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We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and…

General Relativity and Quantum Cosmology · Physics 2014-12-09 Jose M. Torres , Miguel Alcubierre , Alberto Diez-Tejedor , Dario Nunez

It is known than the inclusion of spatial curvature can modify the evolution of matter perturbations and affect the Large Scale Structure (LSS) formation. We quantify the effects of the non-zero space curvature in terms of LSS formation for…

General Relativity and Quantum Cosmology · Physics 2020-12-08 Jhonny A. Agudelo Ruiz , Júlio C. Fabris , Alan M. Velasquez-Toribio , Ilya L. Shapiro

We calculate the one-point probability distribution function (PDF) for cosmic density in non-linear regime of the gravitational evolution. Under the local approximation that the evolution of cosmic fluid fields can be characterized by the…

Astrophysics · Physics 2009-11-10 Yasuhiro Ohta , Issha Kayo , Atsushi Taruya

The spherical collapse model is often used to follow the evolution of overdensities into the nonlinear regime. We describe the correct approach to be used in coupled dark energy cosmologies, where a fifth force, different from gravity and…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-15 Nico Wintergerst , Valeria Pettorino

Scalar field dark matter offers an interesting alternative to the traditional WIMP dark matter picture. Astrophysical and cosmological simulations are useful to constraining the mass of the dark matter particle in this model. This is…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-13 Andrew Eberhardt , Alvaro Zamora , Michael Kopp , Tom Abel

We explore the real solutions to the Spherical Collapse Model in a non-flat Universe with a Cosmological Constant, and observe a possible situation for a fake or Ghost Collapse, in which an expanding overdense spherical region, turns around…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-26 Aditya Vidhate , Rahul Nigam

We use numerical relativity simulations to describe the spacetime evolution during nonlinear structure formation in $\Lambda$CDM cosmology. Fully nonlinear initial conditions are set at an initial redshift $z\approx 300$, based directly on…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-12 Robyn L. Munoz , Marco Bruni

Using an analytical model, we study the evolution of subhalo, including its mass, angular momentum and merging time-scale. This model considers the dominant processes governing subhalo evolution, such as dynamical friction, tidal stripping…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 JianLing Gan , Xi Kang , Frank C. van den Bosch , JinLiang Hou

We explore the impact of dynamical friction on scales where the linear growth factor and the spherical collapse model can be applied and show its influence on the evolution of perturbations. In particular, considering smooth and clustering…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-25 Francesco Pace , Orlando Luongo , Antonino Del Popolo

Reviewing the semiclassical theory for the parametric level density fluctuations, we show that for large parametric changes the density correlation function, after rescaling, becomes universal and coincides with the leading asymptotic term…

Most prior works studying tidal interactions in tight star/planet or star/star binary systems have employed linear theory of a viscous fluid in a uniformly-rotating two-dimensional spherical shell. However, compact systems may have…

Solar and Stellar Astrophysics · Physics 2023-10-11 Aurélie Astoul , Adrian J. Barker

In this manuscript, we investigate late-time cosmology and the evolution of cosmic structures using an interacting dark fluid model in which dark matter (DM) and dark energy (DE) interact through a diffusive mechanism. To provide a…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 Shambel Sahlu , Upala Mukhopadhyay , Remudin R. Mekuria , Amare Abebe

We use the physics of ellipsoidal collapse to model the probability distribution function of the smoothed dark matter density field in real and redshift space. We provide a simple approximation to the exact collapse model which shows…

Astrophysics · Physics 2008-08-05 Tsz Yan Lam , Ravi K. Sheth

We study the effects of non-hermitian perturbation on a quantum kicked model exhibiting a localization transition. Using an exact renormalization scheme, we show that the critical line separating the extended and localized phases approaches…

Disordered Systems and Neural Networks · Physics 2009-11-07 Indubala I satija , Arjendu Pattanayak

We study a model describing the slow flow of a fluid through a deformable, porous, elastic solid undergoing small deformations. The stress-strain relationship of the solid incorporates nonlinear effects, formulated as a perturbation of the…

Numerical Analysis · Mathematics 2026-04-28 Andrea Bonito , Vivette Girault , Diane Guignard

A new energy-based stochastic extension of the Schrodinger equation for which the wave function collapses after the passage of a finite amount of time is proposed. An exact closed-form solution to the dynamical equation, valid for all…

Quantum Physics · Physics 2009-11-11 Dorje C. Brody , Lane P. Hughston

We construct a three-dimensional, fully relativistic numerical model of a universe filled with an inhomogeneous pressureless fluid, starting from initial data that represent a perturbation of the Einstein-de Sitter model. We then measure…

General Relativity and Quantum Cosmology · Physics 2016-10-11 Eloisa Bentivegna , Marco Bruni

It is known that radial collapse around density peaks can explain the key features of evolution of correlation function in gravitational clustering in three dimensions. The same model also makes specific predictions for two dimensions. In…

Astrophysics · Physics 2009-10-30 J. S. Bagla , S. Engineer , T. Padmanabhan

We apply a recently developed perturbative formalism which describes the evolution under their self-gravity of particles displaced from a perfect lattice to quantify precisely, up to shell crossing, the effects of discreteness in…

Astrophysics · Physics 2008-12-18 Michael Joyce , Bruno Marcos

We consider a time series model involving a fractional stochastic component, whose integration order can lie in the stationary/invertible or nonstationary regions and be unknown, and an additive deterministic component consisting of a…

Statistics Theory · Mathematics 2007-06-13 P. M. Robinson