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We study the effects of projection of three-dimensional (3D) data onto the plane of the sky by means of numerical simulations of turbulence in the interstellar medium including the magnetic field, parameterized cooling and diffuse and…

Testing gravity and the concordance model of cosmology, $\Lambda$CDM, at large scales is a key goal of this decade's largest galaxy surveys. Here we present a comparative study of dark matter power spectrum predictions from different…

In recent years there has been a developing realization that the interesting large--scale structure of voids, ``pancakes", and filaments in the Universe is a consequence of the efficacy of an approximation scheme for cosmological…

Astrophysics · Physics 2009-09-25 Adrian L. Melott , Jennifer L. Pauls

An analytical and numerical study is presented of transmission of radiation through a multi-mode waveguide containing a random medium with a complex dielectric constant $\epsilon= \epsilon'+i\epsilon''$. Depending on the sign of…

Condensed Matter · Physics 2007-05-23 T. Sh. Misirpashaev , J. C. J. Paasschens , C. W. J. Beenakker

We present a new fast and efficient approach to model structure formation with Augmented Lagrangian Perturbation Theory (ALPT). Our method is based on splitting the displacement field into a long and a short-range component. The long-range…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Francisco-Shu Kitaura , Steffen Heß

We describe the construction of an N-body simulation that mimics the true velocity and mass-density fields in a box of side 256\hmpc about the Local Group , and the production of mock catalogs that mimic in detail current catalogs of…

Astrophysics · Physics 2009-10-28 Tsafrir Kolatt , Avishai Dekel , Galit Ganon , Jeffrey Willick

Using high resolution kinetic (VPPM-OMP 1.0) and fluid (BOUT++) solvers, evolution of long-wavelength electron plasma wave (EPW) in the presence of stationary periodic ion background non-uniformity is investigated. Mode coupling dynamics…

Plasma Physics · Physics 2022-06-17 Sanjeev Kumar Pandey , Jagannath Mahapatra , Rajaraman Ganesh

The key to understand the nature of dark energy relies in our ability to probe the distant Universe. In this framework, the recent detection of the kinematic Sunyaev-Zel'dovich (kSZ) effect signature in the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 M. Roncarelli , M. Baldi , F. Villaescusa-Navarro

We propose a new definition of cosmic voids based on methods of Lagrangian orbit reconstruction as well as an algorithm to find them in actual data called DIVA. Our technique is intended to yield results which can be modeled sufficiently…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Guilhem Lavaux , Benjamin D. Wandelt

We present a new suite of over 1,500 cosmological N-body simulations with varied Warm Dark Matter (WDM) models ranging from 2.5 to 30 keV. We use these simulations to train Convolutional Neural Networks (CNNs) to infer WDM particle masses…

We apply a simple linearization, well known in solid state physics, to approximate the evolution at early times of cosmological N-body simulations of gravity. In the limit that the initial perturbations, applied to an infinite perfect…

Astrophysics · Physics 2009-11-11 M. Joyce , B. Marcos , A. Gabrielli , T. Baertschiger , F. Sylos Labini

We present gravitational N-body simulations of the secular morphological evolution of disk galaxies induced by density wave modes. In particular, we address the demands collective effects place on the choice of simulation parameters, and…

Astrophysics of Galaxies · Physics 2016-09-16 Xiaolei Zhang

Intraoperative observation of tissue internal structure is often difficult. Hence, real-time soft tissue deformation is essential for the localization of tumor and other internal structures. We propose a method to simulate the internal…

Computational Geometry · Computer Science 2019-07-26 Haoyin Zhou , Eva Gombos , Mehra Golshan , Jayender Jagadeesan

We present a framework for general relativistic N-body simulations in the regime of weak gravitational fields. In this approach, Einstein's equations are expanded in terms of metric perturbations about a Friedmann-Lema\^itre background,…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Julian Adamek , Ruth Durrer , Martin Kunz

Approximate N-body methods, such as FastPM and COLA, have been successful in modelling halo and galaxy clustering statistics, but their low resolution on small scales is a limitation for applications that require high precision. Full N-body…

Instrumentation and Methods for Astrophysics · Physics 2024-06-18 Yiheng Wu , Hong Guo , Volker Springel

If the accelerated expansion of the Universe at the present epoch is driven by a dark energy scalar field, there may well be a non-trivial coupling between the dark energy and the cold dark matter (CDM) fluid. Such interactions give rise to…

Astrophysics · Physics 2014-11-18 Marco Baldi , Valeria Pettorino , Georg Robbers , Volker Springel

Assuming that a formal approximation of multiple waves has been obtained by matched asymptotic methods, we derive a {\em Spatial Shadowing lemma} to construct exact solutions near the formal approximation. In Part I, we consider a general…

patt-sol · Physics 2014-11-18 Xiao-Biao Lin

Within many-body perturbation theory we apply vertex corrections to various closed-shell atoms and to jellium, using a local approximation for the vertex consistent with starting the many-body perturbation theory from a DFT-LDA Green's…

For given computational resources, the accuracy of plasma simulations using particles is mainly held back by the noise due to limited statistical sampling in the reconstruction of the particle distribution function. A method based on…

Computational Physics · Physics 2009-09-03 Romain Nguyen van yen , Diego del-Castillo-Negrete , Kai Schneider , Marie Farge , Guangye Chen

Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria: numerical qualities (precision and spectral…

Fluid Dynamics · Physics 2008-01-15 Jérôme Boudet , Joëlle Caro , L. Shao , Emmanuel Lévêque
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