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We discuss a new algorithm to generate multi-scale initial conditions with multiple levels of refinements for cosmological "zoom-in" simulations. The method uses an adaptive convolution of Gaussian white noise with a real space transfer…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Oliver Hahn , Tom Abel

At early times dark matter has a thermal velocity dispersion of unknown amplitude which, for warm dark matter models, can influence the formation of nonlinear structure on observable scales. We propose a new scheme to simulate cosmologies…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jens Stücker , Oliver Hahn , Raul E. Angulo , Simon D. M. White

We present a new, simple, fast algorithm to numerically evolve disks of inelastically colliding particles surrounding a central star. Our algorithm adds negligible computational cost to the fastest existing collisionless N-body codes, and…

Astrophysics · Physics 2008-11-26 Yoram Lithwick , Eugene Chiang

Modern `smart' materials have complex microscale structure, often with unknown macroscale closure. The Equation-Free Patch Scheme empowers us to non-intrusively, efficiently, and accurately simulate over large scales through computations on…

Numerical Analysis · Mathematics 2023-01-31 A. J. Roberts , Thien Tran-Duc , J. E. Bunder , Yannis Kevrekidis

Spherical collapse predicts that a single value of the turnaround density (average matter density within the scale on which a structure detaches from the Hubble flow) characterizes all cosmic structures at the same redshift. It has been…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Vasiliki Pavlidou , Giorgos Korkidis , Theodore Tomaras , Dimitrios Tanoglidis

We demonstrate that testing for self-similarity in scale-free simulations provides an excellent tool to quantify the resolution at small scales of cosmological N-body simulations. Analysing two-point correlation functions measured in…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-22 Michael Joyce , Lehman Garrison , Daniel Eisenstein

Image-based surface reconstruction and characterization are crucial for missions to small celestial bodies (e.g., asteroids), as it informs mission planning, navigation, and scientific analysis. Recent advances in Gaussian splatting enable…

Computer Vision and Pattern Recognition · Computer Science 2026-05-12 Jennifer Nolan , Travis Driver , John Christian

The most difficult aspect of the realistic modeling of granular materials is how to capture the real shape of the particles. Here we present a method to simulate granular materials with complex-shaped particles. The particle shape is…

Materials Science · Physics 2008-04-18 F. Alonso-Marroquin , Yucang Wang

Weak lensing has become a powerful tool for probing the matter distribution in the Universe and constraining cosmological parameters. This paper aims to explore the fast mock generation pipeline to obtain the covariance matrix of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-17 Yiming Hu , Yu Yu

A new theory for determining the mass function of cosmic structures is presented. It relies on a realistic treatment of collapse dynamics. Gravitational collapse is analyzed in the Lagrangian perturbative framework. Lagrangian perturbations…

Astrophysics · Physics 2015-06-24 Pierluigi Monaco

The rapidly increasing statistical power of cosmological imaging surveys requires us to reassess the regime of validity for various approximations that accelerate the calculation of relevant theoretical predictions. In this paper, we…

We extend the multi-tracer (MT) formalism of the effective field theory of large-scale structure to redshift space, comparing the results of MT to a single-tracer analysis when extracting cosmological parameters from simulations. We used a…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-12 Thiago Mergulhão , Henrique Rubira , Rodrigo Voivodic

Materials exhibit geometric structures across mesoscopic to microscopic scales, influencing macroscale properties such as appearance, mechanical strength, and thermal behavior. Capturing and modeling these multiscale structures is…

Graphics · Computer Science 2025-04-15 Bojja Venu , Adam Bosak , Juan Raul Padron-Griffe

We present a test to quantify how well some approximate methods, designed to reproduce the mildly non-linear evolution of perturbations, are able to reproduce the clustering of DM halos once the grouping of particles into halos is defined…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Emiliano Munari , Pierluigi Monaco , Jun Koda , Francisco-Shu Kitaura , Emiliano Sefusatti , Stefano Borgani

Current models of galaxy formation applied to understanding the large-scale structure of the universe have two parts. The first is an accurate solution of the equations of motion for the dark matter due to gravitational clustering. The…

Astrophysics · Physics 2009-11-06 Roman Scoccimarro , Ravi K. Sheth

Extracting accurate cosmological information from galaxy-galaxy and galaxy-matter correlation functions on non-linear scales ($\lesssim 10 h^{-1} \mathrm{Mpc}$) requires cosmological simulations. Additionally, one has to marginalise over…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-02 Johannes U. Lange , Frank C. van den Bosch , Andrew R. Zentner , Kuan Wang , Andrew P. Hearin , Hong Guo

Morphological classification conveys abundant information on the formation, evolution, and environment of galaxies. In this work, we refine the two-step galaxy morphological classification framework ({\tt\string USmorph}), which employs a…

Astrophysics of Galaxies · Physics 2024-04-25 Jie Song , GuanWen Fang , Shuo Ba , Zesen Lin , Yizhou Gu , Chichun Zhou , Tao Wang , Cai-Na Hao , Guilin Liu , Hongxin Zhang , Yao Yao , Xu Kong

We present a new high-resolution N-body algorithm for cosmological simulations. The algorithm employs a traditional particle-mesh technique on a cubic grid and successive multilevel relaxations on the finer meshes, introduced recursively in…

Astrophysics · Physics 2009-10-30 Andrey V. Kravtsov , Anatoly A. Klypin , Alexei M. Khokhlov

Multivariate cortico-muscular analysis has recently emerged as a promising approach for evaluating the corticospinal neural pathway. However, current multivariate approaches encounter challenges such as high dimensionality and limited…

We present a numerically cheap approximation to super-sample covariance (SSC) of large scale structure cosmological probes, first in the case of angular power spectra. It necessitates no new elements besides those used for the prediction of…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-17 Fabien Lacasa , Julien Grain