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We study the real-time dynamics of a two-dimensional Anderson--Hubbard model using nonequilibrium self-consistent perturbation theory within the second-Born approximation. When compared with exact diagonalization performed on small…

Disordered Systems and Neural Networks · Physics 2016-03-11 Yevgeny Bar Lev , David R. Reichman

New solutions of 3+1D covariant kinetic theory are presented for nuclear collisions in the energy domain Ecm ~ 200 AGeV. They are obtained using MPC, a new Monte-Carlo parton transport technique that employs very high parton subdivision…

Nuclear Theory · Physics 2009-10-09 Denes Molnar , Miklos Gyulassy

We implement advanced Riemann solvers HLLC and HLLD \cite{Mignone:2005ft,MUB:2009} together with an advanced constrained transport scheme \cite{Gardiner:2007nc} in a numerical-relativity neutrino-radiation magnetohydrodynamics code. We…

High Energy Astrophysical Phenomena · Physics 2023-01-11 Kenta Kiuchi , Loren E. Held , Yuichiro Sekiguchi , Masaru Shibata

We present the implementation of a three-dimensional, second order accurate Godunov-type algorithm for magneto-hydrodynamic (MHD), in the adaptive-mesh-refinement (AMR) cosmological code {\tt CHARM}. The algorithm is based on the full…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Francesco Miniati , Daniel F. Martin

Non-equilibrium effects play a vital role in high-speed and rarefied gas flows and the accurate simulation of these flow regimes are far beyond the capability of near-local-equilibrium Navier-Stokes-Fourier equations. Eu proposed…

Fluid Dynamics · Physics 2016-11-07 Zhongzheng Jiang , Weifang Chen , Wenwen Zhao

Due to the prevalence of magnetic fields in astrophysical environments, magnetohydrodynamic (MHD) simulation has become a basic tool for studying astrophysical fluid dynamics. To further advance the precision of MHD simulations, we have…

High Energy Astrophysical Phenomena · Physics 2023-08-09 Jeongbhin Seo , Dongsu Ryu

We present neutrino-transport algorithms implemented in the toolkit for high-order neutrino-radiation hydrodynamics (thornado) and their coupling to self-gravitating hydrodynamics within the adaptive mesh refinement (AMR)-based multiphysics…

We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by…

Instrumentation and Methods for Astrophysics · Physics 2016-04-27 Albino Perego , Ruben Cabezón , Roger Käppeli

The ideal Magnetohydrodynamics (MHD) equations are challenging because one needs to maintain the divergence free condition, $\nabla \cdot \Bv = 0$. Many numerical methods have been developed to enforce this condition. In this work, we…

Numerical Analysis · Mathematics 2019-08-06 Firat Cakir , Andrew Christlieb , Yan Jiang

We present the new Guided Moments ($\texttt{GM}$) formalism for neutrino modeling in astrophysical scenarios like core-collapse supernovae and neutron star mergers. The truncated moments approximation ($\texttt{M1}$) and Monte-Carlo…

High Energy Astrophysical Phenomena · Physics 2024-03-18 Manuel R. Izquierdo , J. Fernando Abalos , Carlos Palenzuela

We present a new numerical algorithm to solve the recently derived equations of two-moment cosmic ray hydrodynamics (CRHD). The algorithm is implemented as a module in the moving mesh Arepo code. Therein, the anisotropic transport of cosmic…

High Energy Astrophysical Phenomena · Physics 2021-02-24 Timon Thomas , Christoph Pfrommer , Rüdiger Pakmor

Solving the Euler equations of ideal hydrodynamics as accurately and efficiently as possible is a key requirement in many astrophysical simulations. It is therefore important to continuously advance the numerical methods implemented in…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-02 Kevin Schaal , Andreas Bauer , Praveen Chandrashekar , Rüdiger Pakmor , Christian Klingenberg , Volker Springel

We provide a detailed description of the Chimera code, a code developed to model core collapse supernovae in multiple spatial dimensions. The core collapse supernova explosion mechanism remains the subject of intense research. Progress to…

Direct simulation of physical processes on a kinetic level is prohibitively expensive in aerospace applications due to the extremely high dimension of the solution spaces. In this paper, we consider the moment system of the Boltzmann…

Numerical Analysis · Mathematics 2021-06-18 Steffen Schotthöfer , Tianbai Xiao , Martin Frank , Cory D. Hauck

In this work, we develop reduced order models (ROMs) to predict solutions to a multiscale kinetic transport equation with a diffusion limit under the parametric setting. When the underlying scattering effect is not sufficiently strong, the…

Numerical Analysis · Mathematics 2025-05-14 Tianyu Jin , Zhichao Peng , Yang Xiang

This paper develops a modified version of the Boltzmann equation for micro-scale particulate flow with capture and diffusion that describes the colloidal-suspension-nano transport in porous media. An equivalent sink term is introduced into…

Fluid Dynamics · Physics 2020-01-23 Oleg Dinariev , Afonso Rego , Pavel Bedrikovetsky

We report on the development of a test-particle based kinetic Monte Carlo code for large systems and its application to simulate matter in the continuum regime. Our code combines advantages of the Direct Simulation Monte Carlo and the…

Fluid Dynamics · Physics 2014-07-31 Irina Sagert , Wolfgang Bauer , Dirk Colbry , Rodney Pickett , Terrance Strother

Transport phenomena-describing the movement of particles, energy, or other physical quantities-are fundamental in various scientific disciplines, including nuclear physics, plasma physics, astrophysics, engineering, and the natural…

Numerical Analysis · Mathematics 2025-06-06 Nicola Cavallini , Gianmarco Manzini , Daniele Funaro , Andrea Favalli

A collision-based hybrid algorithm for the discrete ordinates approximation of the neutron transport equation is extended to the multigroup setting. The algorithm uses discrete energy and angle grids at two different resolutions and…

Computational Physics · Physics 2022-12-05 Ben Whewell , Ryan G. McClarren , Cory D. Hauck , Minwoo Shin

We present a new three-dimensional general-relativistic hydrodynamic evolution scheme coupled to dynamical spacetime evolutions which is capable of efficiently simulating stellar collapse, isolated neutron stars, black hole formation, and…

High Energy Astrophysical Phenomena · Physics 2013-09-23 C. Reisswig , R. Haas , C. D. Ott , E. Abdikamalov , P. Moesta , D. Pollney , E. Schnetter
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