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Related papers: A Phase-Space Approach to Collisionless Stellar Sy…

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Reciprocal space methods for solving Poisson's equation for finite charge distributions are investigated. Improvements to previous proposals are presented, and their performance is compared in the context of a real-space density functional…

Computational Physics · Physics 2007-05-23 Alberto Castro , Angel Rubio , M. J. Stott

We study solutions of the collisionless Boltzmann equation (CBE) in a functional Koopman representation. This facilitates the use of linear spectral techniques characteristic of the analysis of Schrodinger-type equations. For illustrative…

Astrophysics of Galaxies · Physics 2024-06-25 Keir Darling , Lawrence M. Widrow

We present a new hybrid lattice-Boltzmann and Langevin molecular dynamics scheme for simulating the dynamics of suspensions of spherical colloidal particles. The solvent is modeled on the level of the lattice-Boltzmann method while the…

Soft Condensed Matter · Physics 2007-06-20 Vladimir Lobaskin , Burkhard Duenweg

The purpose of this paper is to propose a time-step-robust cell-to-cell integration of particle trajectories in 3-D unstructured meshes in particle/mesh Lagrangian stochastic methods. The main idea is to dynamically update the mean fields…

Computation · Statistics 2023-04-19 Guilhem Balvet , Jean-Pierre Minier , Christophe Henry , Yelva Roustan , Martin Ferrand

Einstein's field equations for spatially self-similar spherically symmetric perfect-fluid models are investigated. The field equations are rewritten as a first-order system of autonomous differential equations. Dimensionless variables are…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Martin Goliath , Ulf S Nilsson , Claes Uggla

The concept of diffusion in collisionless space plasmas like those near the magnetopause and in the geomagnetic tail is reexamined from a fundamental statistical point of view making use of the division of particle orbits into waiting…

Space Physics · Physics 2014-06-25 R. A. Treumann , W. Baumjohann

The Liouville theorem states that the phase-space volume of an ensemble in a closed system remains constant. While gases of material particles can efficiently be cooled by sympathetic or laser cooling techniques, allowing for large…

Every probability distribution can be approximated up to a given precision by a phase-type distribution, i.e. a distribution encoded by a continuous time Markov chain (CTMC). However, an excessive number of states in the corresponding CTMC…

Performance · Computer Science 2014-07-01 Ľuboš Korenčiak , Jan Krčál , Vojtěch Řehák

The aim of this paper is to investigate the unstable nature of pressure computation focusing on incompressible flow modeling through the projection-based particle methods. A new approach from the original viewpoint of the momentum…

Fluid Dynamics · Physics 2022-03-18 Liang-Yee Cheng , Rubens Augusto Amaro Junior , Eric Henrique Favero

We present a real-space formulation and higher-order finite-difference implementation of periodic Orbital-free Density Functional Theory (OF-DFT). Specifically, utilizing a local reformulation of the electrostatic and kernel terms, we…

Computational Physics · Physics 2015-12-23 Swarnava Ghosh , Phanish Suryanarayana

We investigate how accurately phase space distribution functions (DFs) in galactic models can be reconstructed by a made-to-measure (M2M) method, which constructs $N$-particle models of stellar systems from photometric and various kinematic…

Astrophysics of Galaxies · Physics 2016-08-24 Hiromichi Tagawa , Naoteru Gouda , Taihei Yano , Takuji Hara

Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision…

Computational Physics · Physics 2013-06-13 Kalyan S. Perumalla , Vladimir A. Protopopescu

Computing stationary states is an important topic for phase field crystal (PFC) models. Great efforts have been made for energy dissipation of the numerical schemes when using gradient flows. However, it is always time-consuming due to the…

Numerical Analysis · Mathematics 2019-09-04 Kai Jiang , Wei Si , Chenglong Bao

Motivated by a heat radiative transport equation, we consider a particle undergoing collisions in a space-time domain and propose a method to sample its escape time, space and direction from the domain. The first step of the procedure is an…

Computational Physics · Physics 2024-10-22 Laetitia Laguzet , Gabriel Turinici

We present an approach to the design of distribution functions that depend on the phase-space coordinates through the action integrals. The approach makes it easy to construct a dynamical model of a given stellar component. We illustrate…

Astrophysics of Galaxies · Physics 2015-06-23 Lorenzo Posti , James Binney , Carlo Nipoti , Luca Ciotti

We present here the first stellar models on the Hertzsprung-Russell diagram (HRD), in which convection is treated according to the novel scale-free convection theory (SFC theory) by Pasetto et al. (2014). The aim is to compare the results…

Solar and Stellar Astrophysics · Physics 2016-04-27 S. Pasetto , C. Chiosi , E. Chiosi , M. Cropper , A. Weiss

We investigate the probability distribution function of the free flight time and of the number of collisions in a hard sphere gas at equilibrium. At variance with naive expectation, the latter quantity does not follow Poissonian statistics,…

Statistical Mechanics · Physics 2008-04-24 P. Visco , F. van Wijland , E. Trizac

We investigate the equilibrium properties of bcc-liquid interfaces modeled with a continuum phase-field crystal (PFC) approach [K. R. Elder and M. Grant, Phys. Rev. E 70, 051605 (2004)]. A multiscale analysis of the PFC model is carried out…

Materials Science · Physics 2009-11-13 Kuo-An Wu , Alain Karma

In the smoothed particle dynamics (SPH) method, the characteristics of a target particle are interpolated based on the information from its neighboring particles. Consequently, a uniform initial distribution of particles significantly…

Computational Engineering, Finance, and Science · Computer Science 2024-09-27 Chenxi Zhao , Yongchuan Yu , Oskar J. Haidn , Xiangyu Hu

In this work we propose a Hybrid method with Deviational Particles (HDP) for a plasma modeled by the inhomogeneous Vlasov-Poisson-Landau system. We split the distribution into a Maxwellian part evolved by a grid based fluid solver and a…

Numerical Analysis · Mathematics 2016-02-17 Bokai Yan