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A spatially-periodic longitudinal wave is considered in relativistic dissipative hydrodynamics. At sufficiently small wave amplitudes, an analytic solution is obtained in the linearised limit of the macroscopic conservation equations within…

Fluid Dynamics · Physics 2018-03-07 Victor E. Ambrus

Examination of the Einstein energy-momentum relationship suggests that simple unbound forms of matter exist in a four-dimensional Euclidean space. Position, momentum, velocity, and other vector quantities can be expressed as Euclidean…

Quantum Physics · Physics 2007-05-23 Paul J. Freitas

We introduce a non-exponential radiative framework that takes into account the local spatial correlation of scattering particles in a medium. Most previous works in graphics have ignored this, assuming uncorrelated media with a uniform,…

Graphics · Computer Science 2018-05-14 Adrian Jarabo , Carlos Aliaga , Diego Gutierrez

A new and very general technique for simulating solid-fluid suspensions is described; its most important feature is that the computational cost scales linearly with the number of particles. The method combines Newtonian dynamics of the…

comp-gas · Physics 2009-10-22 Anthony J. C. Ladd

We derive the equations of motion of relativistic, non-resistive, second-order dissipative magnetohydrodynamics from the Boltzmann equation using the method of moments. We assume the fluid to be composed of a single type of point-like…

We derive the Boltzmann equation in the context of a gravity theory with non-minimal coupling between matter and curvature. We show that as the energy-momentum tensor is not conserved in these theories, it follows a condition on the…

General Relativity and Quantum Cosmology · Physics 2020-10-28 Orfeu Bertolami , Cláudio Gomes

A set of integral relations for rotational and translational zero modes in the vicinity of the classical soliton solution are derived from the particle-like properties of the latter. The validity of these all relations is considered for a…

High Energy Physics - Theory · Physics 2007-05-23 Andrei Dubikovsky

We show that the widely used relaxation time approximation to the relativistic Boltzmann equation contains basic flaws, being incompatible with microscopic and macroscopic conservation laws. We propose a new approximation that fixes such…

Nuclear Theory · Physics 2021-07-28 Gabriel S. Rocha , Gabriel S. Denicol , Jorge Noronha

In this paper, we consider the Boltzmann equation with respect to orthonormal vielbein fields in conservative form. This formalism allows the use of arbitrary coordinate systems to describe the space geometry, as well as of an adapted…

Fluid Dynamics · Physics 2019-04-02 Sergiu Busuioc , Victor E. Ambrus

We use a macroscopic description of a system of relativistic particles based on adding a nonequilibrium tensor to the usual hydrodynamic variables. The nonequilibrium tensor is linked to relativistic kinetic theory through a nonlinear…

Nuclear Theory · Physics 2015-06-12 J. Peralta-Ramos , E. Calzetta

The Boltzmann equation for inelastic and rough hard spheres is considered as a model of a dilute granular gas. In this model, the collisions are characterized by constant coefficients of normal and tangential restitution and hence the…

Statistical Mechanics · Physics 2014-09-03 Gilberto M. Kremer , Andrés Santos , Vicente Garzó

We reconstruct a 3+1 formalism of general relativistic electromagnetism, and derive the equations of motion of charged particles in the pulsar magnetosphere, taking account of the inclination between the rotation axis and the magnetic axis.…

Astrophysics · Physics 2009-11-07 Nobuyuki Sakai , Shinpei Shibata

We present a new method for neutrino-matter coupling in multi-dimensional radiation-hydrodynamic simulations of core-collapse supernova (CCSN) with the full Boltzmann neutrino transport. The development is motivated by the fact that the…

High Energy Astrophysical Phenomena · Physics 2019-08-07 Hiroki Nagakura , Kohsuke Sumiyoshi , Shoichi Yamada

We consider the relativistic hydrodynamics of non-perfect fluids with the goal of determining a formulation that is suited for numerical integration in special-relativistic and general-relativistic scenarios. To this end, we review the…

General Relativity and Quantum Cosmology · Physics 2023-02-27 Michail Chabanov , Luciano Rezzolla , Dirk H. Rischke

Dynamical symmetries of the collisionless Boltzmann transport equation, or Vlasov equation, but under the influence of an external driving force, are derived from non-standard representations of the $2D$ conformal algebra. In the case…

Mathematical Physics · Physics 2015-09-08 Stoimen Stoimenov , Malte Henkel

We report on the core-collapse supernova simulation we conducted for a 11.2 M progenitor model in three-dimensional space up to 20 ms after bounce, using a radiation hydrodynamics code with full Boltzmann neutrino transport. We solve the…

High Energy Astrophysical Phenomena · Physics 2020-11-11 Wakana Iwakami , Hirotada Okawa , Hiroki Nagakura , Akira Harada , Shun Furusawa , Kosuke Sumiyoshi , Hideo Matsufuru , Shoichi Yamada

We develop a 3+1+1 covariant formalism with cosmological and astrophysical applications. First we give the evolution and constraint equations both on the brane and off-brane in terms of 3-space covariant kinematical,…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Zoltán Keresztes , László Á. Gergely

We find a choice of variables for the 3+1 formulation of general relativity which casts the evolution equations into (flux-conservative) symmetric-hyperbolic first order form for arbitrary lapse and shift, for the first time. We redefine…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Simonetta Frittelli , Oscar Reula

We developed a new general-relativistic quantum-kinetics neutrino transport code, GRQKNT, for numerical studies of quantum kinetics of non-equilibrium neutrinos in six-dimensional phase space. This code is intended for use in both local and…

High Energy Astrophysical Phenomena · Physics 2022-10-05 Hiroki Nagakura

In this work I develop a new framework for anisotropic hydrodynamics that generalizes the leading order of the hydrodynamic expansion to the full (3+1)-dimensional anisotropic massive case. Following previous works, my considerations are…

Nuclear Theory · Physics 2015-07-29 Leonardo Tinti