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Two-moment neutrino transport methods have been widely used for developing theoretical models of core-collapse supernova (CCSN), since they substantially reduce the computational burden inherent in the multi-dimensional neutrino-radiation…

High Energy Astrophysical Phenomena · Physics 2021-07-07 Hiroki Nagakura , Lucas Johns

We develop a numerical code to calculate the neutrino transfer with multi-energy and multi-angle in three dimensions (3D) for the study of core-collapse supernovae. The numerical code solves the Boltzmann equations for neutrino…

High Energy Astrophysical Phenomena · Physics 2012-03-26 Kohsuke Sumiyoshi , Shoichi Yamada

We outline the non-perturbative theory of multiple scattering of resonant, intense laser light off a dilute cloud of cold atoms. A combination of master equation and diagrammatic techniques allows, for the first time, a quantitative…

Quantum Physics · Physics 2019-09-18 Tobias Binninger , Vyacheslav N. Shatokhin , Andreas Buchleitner , Thomas Wellens

The semi-classical Bloch-Boltzmann theory is at the heart of our understanding of conduction in solids, ranging from metals to semi-conductors. Physical systems that are beyond the range of applicability of this theory are thus of…

Materials Science · Physics 2007-12-18 Didier Mayou , Guy Trambly De Laissardière

We discuss general features of charge transport in non-relativistic classical field theories invariant under non-abelian unitary Lie groups by examining the full structure of two-point dynamical correlation functions in grand-canonical…

Statistical Mechanics · Physics 2021-01-04 Žiga Krajnik , Enej Ilievski , Tomaž Prosen

We study the multi-dimensional properties of neutrino transfer inside supernova cores by solving the Boltzmann equations for neutrino distribution functions in genuinely six dimensional (6D) phase space. Adopting representative snapshots of…

High Energy Astrophysical Phenomena · Physics 2014-12-30 K. Sumiyoshi , T. Takiwaki , H. Matsufuru , S. Yamada

Aims. Numerical test-particle simulations are a reliable and frequently used tool to test analytical transport theories and to predict mean-free paths. The comparison between solutions of the diffusion equation and the particle flux is used…

High Energy Astrophysical Phenomena · Physics 2016-02-17 R. C. Tautz , J. Bolte , A. Shalchi

In the continuation of our previous work, the transverse momentum ($p_T$) spectra and nuclear modification factor ($R_{AA}$) are derived using relaxation time approximation of Boltzmann Transport Equation (BTE). The initial…

Nuclear Theory · Physics 2017-05-19 Sushanta Tripathy , Arvind Khuntia , Swatantra Kumar Tiwari , Raghunath Sahoo

In two-particle angular correlation measurements the distribution of charged hadron pairs are evaluated as a function of pseudorapidity ($\Delta \eta$) and azimuthal ($\Delta \varphi$) differences. In these correlations, jets manifest…

High Energy Physics - Phenomenology · Physics 2019-04-02 Balázs Endre Szigeti , Monika Varga-Kofarago

Neutrinos are densely populated deep inside the core of massive stars after their gravitational collapse to produce supernova explosions and form compact stars such as neutron stars (NS) and black holes (BH). It has been considered that…

High Energy Astrophysical Phenomena · Physics 2019-05-29 Milad Delfan Azari , Shoichi Yamada , Taiki Morinaga , Wakana Iwakami , Hirotada Okawa , Hiroki Nagakura , Kohsuke Sumiyoshi

The transport of energetic charged particles (e.g., cosmic rays) in turbulent magnetic fields is usually characterized in terms of the diffusion parallel and perpendicular to a large-scale (or mean) magnetic field. The nonlinear guiding…

Plasma Physics · Physics 2022-07-06 A. P. Snodin , T. Jitsuk , D. Ruffolo , W. H. Matthaeus

An anisotropic random barrier model is presented, in which the transition probabilities in different directions have different probability density functions. At low temperatures, the anisotropic long--time diffusion coefficients, obtained…

Disordered Systems and Neural Networks · Physics 2009-11-10 Sebastian Bustingorry

A three-dimensional Monte Carlo code for modelling radiation transport in Type Ia supernovae is described. In addition to tracking Monte Carlo quanta to follow the emission, scattering and deposition of radiative energy, a scheme involving…

Astrophysics · Physics 2008-11-26 S. A. Sim

The transport of charged particles in the heliosphere and the interstellar medium is governed by the interaction of particles and magnetic irregularities. For the transport of protons a rather simple model using a linear Alfv\'en wave…

High Energy Astrophysical Phenomena · Physics 2015-12-16 Cedric Schreiner , Felix Spanier

We numerically study the dynamics of cold atoms in a two-dimensional disordered potential. We consider an anisotropic speckle potential and focus on the classical regime, which is relevant to some recent experiments. First, we study the…

General relativistic radiation hydrodynamics simulations are necessary to accurately model a number of astrophysical systems involving black holes and neutron stars. Photon transport plays a crucial role in radiatively dominated accretion…

High Energy Astrophysical Phenomena · Physics 2018-01-31 Francois Foucart

An open source software package for simulating thermal neutron propagation in geometry is presented. In this system, neutron propagation can be treated by either the particle transport method or the ray-tracing method. Supported by an…

Computational Physics · Physics 2023-12-05 Zi-Yi Pan , Ni Yang , Ming Tang , Peixun Shen , Xiao-Xiao Cai

In this paper, we present results from a simulation of stellar core collapse, bounce, and postbounce evolution with Boltzmann neutrino transport. We motivate the development of our Boltzmann solver in light of the sensitivity of the…

Astrophysics · Physics 2009-10-31 A. Mezzacappa

A popular numerical method to model the dynamics of a 'full spectrum' of cosmic rays (CRs), also applicable to radiation/neutrino hydrodynamics (RHD), is to discretize the spectrum at each location/cell as a piecewise power law in 'bins' of…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Philip F. Hopkins

We investigate the diffusive electron-transport properties of charge-doped graphene ribbons and nanoribbons with imperfect edges. We consider different regimes of edge scattering, ranging from wide graphene ribbons with (partially)…