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Neutrino transport in compact objects is an inherently challenging multi-dimensional problem. This difficulty is compounded if one includes flavor transformation -- an intrinsically quantum phenomenon requiring one to follow the coherence…

High Energy Astrophysical Phenomena · Physics 2025-05-14 Evan Grohs , Sherwood Richers , Julien Froustey , Francois Foucart , James P. Kneller , Gail C. McLaughlin

The Boltzmann equation has been a driving force behind significant mathematical research over the years. Its challenging theoretical complexity, combined with a wide variety of current scientific and technological problems that require…

Mathematical Physics · Physics 2026-03-11 Liliane Basso Barichello

Employing the nonequilibrium Green's function method, we develop a fully quantum mechanical model to study the coupled electron-phonon transport in one-dimensional atomic junctions in the presence of a weak electron-phonon interaction. This…

Mesoscale and Nanoscale Physics · Physics 2008-03-04 J. T. Lü , Jian-Sheng Wang

We use an adiabatic approximation in terms of instantaneous resonances to study the steady-state and time-dependent transport properties of interacting electrons in biased resonant tunneling heterostructures. This approach leads, in a…

Condensed Matter · Physics 2009-10-28 Carlo Presilla , Johannes Sjöstrand

Simulations of pulverised coal combustion rely on various models, required in order to correctly approximate the flow, chemical reactions, and behavior of solid particles. These models, in turn, rely on multiple model parameters, which are…

Chemical Physics · Physics 2021-02-24 Ahmed Hassan , Taraneh Sayadi , Vincent LeChenadec , Heinz Pitsch , Antonio Attili

A transport theory is developed on the quark level to describe nucleon--nucleon collisions. We treat the strong interaction effectively by the Friedberg-Lee model both in its original and in its modified confining version. First we study…

Nuclear Theory · Physics 2009-10-28 T. Vetter T. S. Biro U. Mosel

The paper contributes to strengthening the relation between machine learning and the theory of differential equations. In this context, the inverse problem of fitting the parameters, and the initial condition of a differential equation to…

Machine Learning · Computer Science 2022-06-22 Imre Fekete , András Molnár , Péter L. Simon

Tunneling hetero-junctions (THJs) usually induce confined states at the regions close to the tunnel junction which significantly affect their transport properties. Accurate numerical modeling of such effects requires combining the…

Mesoscale and Nanoscale Physics · Physics 2017-08-02 Tarek A. Ameen , Hesameddin Ilatikhameneh , Jun Z. Huang , Michael Povolotskyi , Rajib Rahman , Gerhard Klimeck

This paper is concerned with the convergence of a two-step modified Newton method for solving the nonlinear system arising from the minimal nonnegative solution of nonsymmetric algebraic Riccati equations from neutron transport theory. We…

Numerical Analysis · Mathematics 2025-07-22 Juan Liang , Yonghui Ling

We consider in this contribution a simplified idealized one-dimensional model in a nuclear core reactor coupling the diffusion equation on the neutron flux withthe enthalpy equation for the water which collects the heat produced by this…

Numerical Analysis · Mathematics 2025-03-11 Olivier Lafitte , François Dubois

Consider neutron transport equations in 3D convex domains with in-flow boundary. We mainly study the asymptotic limits as the Knudsen number $\epsilon\rightarrow 0^+$. Using Hilbert expansion, we rigorously justify that the solution of…

Analysis of PDEs · Mathematics 2020-10-05 Lei Wu

The analytical solution of neutron transport equation has fascinated mathematicians and physicists alike since the Milne half-space problem was introduce in 1921 [1]. Numerous numerical solutions exist, but understandably, there are only a…

Computational Physics · Physics 2020-07-07 Barry Ganapol

One route to improved predictive modeling of magnetically confined fusion reactors is to couple transport solvers with direct numerical simulations (DNS) of turbulence, rather than with surrogate models. An additional challenge presented by…

Plasma Physics · Physics 2018-07-16 Jeffrey B. Parker , Lynda L. LoDestro , Alejandro Campos

It is of crucial importance to be able to identify the location of atmospheric pollution sources in our planet. Global models of atmospheric transport in combination with diverse Earth observing systems are a natural choice to achieve this…

Numerical Analysis · Mathematics 2013-11-26 Mauricio Santillana

We study a novel alternative approach for the computation of transport coefficients at mesoscales. While standard nonequilibrium molecular dynamics (NEMD) approaches fix the forcing and measure the average induced flux in the system driven…

Computational Physics · Physics 2025-09-05 Xinyi Wu , Xiaocheng Shang

The adjoint method, recently introduced by Evans, is used to study obstacle problems, weakly coupled systems, cell problems for weakly coupled systems of Hamilton-Jacobi equations, and weakly coupled systems of obstacle type. In particular,…

Analysis of PDEs · Mathematics 2013-03-13 Filippo Cagnetti , Diogo Gomes , Hung Tran

The transport properties of a conduction junction model characterized by two mutually coupled channels that strongly differ in their couplings to the leads are investigated. Models of this type describe molecular redox junctions (where a…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 Alexander J. White , Agostino Migliore , Michael Galperin , Abraham Nitzan

In recent years, the use of adjoint vectors in Computational Fluid Dynamics (CFD) has seen a dramatic rise. Their utility in numerous applications, including design optimization, data assimilation, and mesh adaptation has sparked the…

Computational Engineering, Finance, and Science · Computer Science 2017-12-05 Steven M. Kast

In this Letter, we clarify the physical origin of effective transport in periodic and tilted periodic systems. When Brownian dynamics is examined on the scale of a single period, the particle displacement admits a natural separation into a…

Statistical Mechanics · Physics 2026-01-27 Sang Yang , Zhixin Peng

In this work we present a solution of the one-dimensional spherical symmetric time-dependent neutron transport equation (written for a moving system in lagrangian coordinates) by using the characteristic method. One of the objectives is to…

Computational Physics · Physics 2025-12-18 Dalton Ellery Girao Barroso