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Related papers: An adaptive algorithm for n-body field expansions

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I propound a non-linear generalization of the Poisson equation describing a "medium" in D dimensions with a "dielectric constant" proportional to the field strength to the power D-2. It is the only conformally invariant scalar theory that…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Mordehai Milgrom

Resolving numerically Vlasov-Poisson equations for initially cold systems can be reduced to following the evolution of a three-dimensional sheet evolving in six-dimensional phase-space. We describe a public parallel numerical algorithm…

Computational Physics · Physics 2016-06-29 Thierry Sousbie , Stéphane Colombi

We present a new N-body code, gevolution, for the evolution of large scale structure in the Universe. Our code is based on a weak field expansion of General Relativity and calculates all six metric degrees of freedom in Poisson gauge.…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-05 Julian Adamek , David Daverio , Ruth Durrer , Martin Kunz

For the Poisson equation posed in a domain containing a large number of polygonal perforations, we propose a low-dimensional coarse approximation space based on a coarse polygonal partitioning of the domain. Similarly to other multiscale…

Numerical Analysis · Mathematics 2024-04-17 Miranda Boutilier , Konstantin Brenner , Victorita Dolean

The position-based dynamics (PBD) algorithm is a popular and versatile technique for real-time simulation of deformable bodies, but is only applicable to forces that can be expressed as linearly compliant constraints. In this work, we…

Graphics · Computer Science 2025-12-01 Manas Chaudhary , Chandradeep Pokhariya , Rahul Narain

The wave functions of Boson and Fermion gases are known even when the particles have harmonic interactions. Here we generalise these results by solving exactly the N-body Schrodinger equation for potentials V that can be any function of the…

Statistical Mechanics · Physics 2009-10-31 D. Lynden-Bell , R. M. Lynden-Bell

The Poisson-Nernst-Planck (PNP) equations are one of the most effective model for describing electrostatic interactions and diffusion processes in ion solution systems, and have been widely used in the numerical simulations of biological…

Numerical Analysis · Mathematics 2023-12-19 Yang Liu , Shi Shu , Ying Yang

This paper formulates a new particle-in-cell method for the Vlasov-Maxwell system. Under the Lorenz gauge condition, Maxwell's equations for the electromagnetic fields can be written as a collection of scalar and vector wave equations. The…

Plasma Physics · Physics 2024-01-18 Andrew J. Christlieb , William A. Sands , Stephen White

We revisit the issue of interpreting the results of large volume cosmological simulations in the context of large scale general relativistic effects. We look for simple modifications to the nonlinear evolution of the gravitational potential…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-17 Oliver Hahn , Aseem Paranjape

In high-temperature plasma physics, a strong magnetic field is usually used to confine charged particles. Therefore, for studying the classical mathematical models of the physical problems it is needed to consider the effect of external…

Numerical Analysis · Mathematics 2023-10-11 Anjiao Gu , Yajuan Sun

We establish a new self-consistent system of equations accounting for a nonminimal coupling of the cooperative gravitational, electromagnetic and pseudoscalar (axion) fields in a multi-component relativistic plasma. The axionic extension of…

General Relativity and Quantum Cosmology · Physics 2013-12-02 Alexander B. Balakin , Ruslan K. Muharlyamov , Alexei E. Zayats

We present a new algorithm for efficiently computing the $N$-point correlation functions (NPCFs) of a 3D density field for arbitrary $N$. This can be applied both to a discrete spectroscopic galaxy survey and a continuous field. By…

Instrumentation and Methods for Astrophysics · Physics 2021-10-27 Oliver H. E. Philcox , Zachary Slepian , Jiamin Hou , Craig Warner , Robert N. Cahn , Daniel J. Eisenstein

A general approach was proposed in this article to develop high-order exponentially fitted basis functions for finite element approximations of multi-dimensional drift-diffusion equations for modeling biomolecular electrodiffusion…

Numerical Analysis · Mathematics 2013-02-13 Melissa R. Swager , Y. C. Zhou

We propose an efficient algorithm for the evaluation of the potential and its gradient of gravitational/electrostatic $N$-body systems, which we call particle mesh multipole method (PMMM or PM$^3$). PMMM can be understood both as an…

Instrumentation and Methods for Astrophysics · Physics 2014-10-20 Keigo Nitadori

In order to approach the pion--multinucleon problem, we have found it convenient to reformulate the general N--body theory starting from the fully unclusterized (i.e., N <- N) amplitude. If we rewrite such an amplitude in terms of new…

Nuclear Theory · Physics 2009-10-28 G. Cattapan , L. Canton

I use N-body simulations with two mass species of particles to demonstrate that disk galaxy simulations are subject to collisional relaxation at a higher rate than is widely assumed. Relaxation affects the vertical thickness of the disk…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 J. A. Sellwood

In this work, we leverage the Hamiltonian kind structure for accurate uncertainty propagation through a nonlinear dynamical system. The developed approach utilizes the fact that the stationary probability density function is purely a…

Optimization and Control · Mathematics 2024-11-19 Amit Jain , Puneet Singla , Roshan Eapen

The diversity of structures in the Universe (from the smallest galaxies to the largest superclusters) has formed under the pull of gravity from the tiny primordial perturbations that we see imprinted in the cosmic microwave background. A…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-01 Matthieu Schaller , Claude Becker , Oleg Ruchayskiy , Alexey Boyarsky , Mikhail Shaposhnikov

We consider an analytic way to make the interacting N-body problem tractable by using harmonic oscillators in place of the relevant two-body interactions. The two body terms of the N-body Hamiltonian are approximated by considering the…

Quantum Gases · Physics 2012-05-16 J. R. Armstrong , N. T. Zinner , D. V. Fedorov , A. S. Jensen

We have measured the probability distribution function (PDF) of cosmic matter density field from a suite of N-body simulations. We propose the generalized normal distribution of version 2 (Nv2) as an alternative fitting formula to the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Jihye Shin , Juhan Kim , Christophe Pichon , Donghui Jeong , Changbom Park