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We derive new equations using the mixed-frame approach for one- and two-dimensional (axisymmetric) time-dependent radiation transport and the associated couplings with matter. Our formulation is multi-group and multi-angle and includes…

Astrophysics · Physics 2011-02-11 Ivan Hubeny , Adam Burrows

The first order condition of the constrained minimization problem leads to a saddle point problem. A multigrid method using a multiplicative Schwarz smoother for saddle point problems can thus be interpreted as a successive subspace…

Numerical Analysis · Mathematics 2016-01-19 Long Chen

In this paper, we present a neural network approach to address the dynamic unbalanced optimal transport problem on surfaces with point cloud representation. For surfaces with point cloud representation, traditional method is difficult to…

Mathematical Physics · Physics 2025-04-23 Jiangong Pan , Wei Wan , Yuejin Zhang , Chenlong Bao , Zuoqiang Shi

A control optimization approach is presented for a chaser spacecraft tasked with maintaining proximity to a target space object while avoiding collisions. The target object trajectory is provided numerically to account for both passive…

Optimization and Control · Mathematics 2025-07-01 Saif R. Kazi , Harsha Nagarajan , Hassan Hijazi , Przemek Wozniak

We develop a neutrino transfer code for core-collapse simulations, that directly solves the multidimensional Boltzmann equations in full general relativity. We employ the discrete ordinate method, which discretizes the six dimensional phase…

Broyden's method, widely used in quantum chemistry electronic-structure calculations for the numerical solution of nonlinear equations in many variables, is applied in the context of the nuclear many-body problem. Examples include the…

To support exactly tracking a neutron moving along a given line segment through a CAD model with quadric surfaces, this paper considers the arithmetic precision required to compute the order of intersection points of two quadrics along the…

Computational Geometry · Computer Science 2016-05-19 Michael Deakin , Jack Snoeyink

Noise-assisted transport phenomena highlight the nontrivial interplay between environmental effects and quantum coherence in achieving maximal efficiency. Due to the complexity of biochemical systems and their environments, effective open…

We provide a generic scheme to separate the particles of a mixture by their physical properties like mass, friction or size. The scheme employs a periodically shaken two dimensional dissipative lattice and hinges on a simultaneous transport…

Chaotic Dynamics · Physics 2018-05-30 Aritra K. Mukhopadhyay , Benno Liebchen , Peter Schmelcher

Accurate neutrino transport has been built into spherically symmetric simulations of stellar core collapse and postbounce evolution. The results of such simulations agree that spherically symmetric models with standard microphysical input…

Astrophysics · Physics 2010-05-12 M. Liebendoerfer , M. Rampp , H. -Th. Janka , A. Mezzacappa

The multinucleon transfer reactions near barrier energies has been investigated with a multistep model based on the dinuclear system (DNS) concept, in which the capture of two colliding nuclei, the transfer dynamics and the de-excitation…

Nuclear Theory · Physics 2018-01-03 Fei Niu , Peng-Hui Chen , Ya-Fei Guo , Chun-Wang Ma , Zhao-Qing Feng

We formulate a generalization of the Glauber formalism for hadron-nucleus and nucleus-nucleus collisions based on the Pomeron approach to high energy interactions. Our treatment is based on two physical assumptions (i.e. two small…

High Energy Physics - Phenomenology · Physics 2019-08-17 S. Bondarenko , E. Gotsman , E. Levin , U. Maor

The computation of the Minimum Orbital Intersection Distance (MOID) is an old, but increasingly relevant problem. Fast and precise methods for MOID computation are needed to select potentially hazardous asteroids from a large catalogue. The…

Earth and Planetary Astrophysics · Physics 2018-06-22 Jose M. Hedo , Manuel Ruiz , Jesus Pelaez

We evaluate an efficient overset grid method for two-dimensional and three-dimensional particulate flows for small numbers of particles at finite Reynolds number. The rigid particles are discretised using moving overset grids overlaid on a…

Computational Physics · Physics 2017-05-24 A. R. Koblitz , S. Lovett , N. Nikiforakis , W. D. Henshaw

This paper continues our treatment of the Neutron Transport Equation (NTE) building on the work in [arXiv:1809.00827v2], [arXiv:1810.01779v4] and [arXiv:1901.00220v3], which describes the flux of neutrons through inhomogeneous fissile…

Probability · Mathematics 2021-10-11 Alexander M. G. Cox , Simon C. Harris , Andreas E. Kyprianou , Minmin Wang

This paper presents an optimization-based receding horizon trajectory planning algorithm for dynamical systems operating in unstructured and cluttered environments. The proposed approach is a two-step procedure that uses a motion planning…

Optimization and Control · Mathematics 2019-12-12 Kristoffer Bergman , Oskar Ljungqvist , Torkel Glad , Daniel Axehill

It has been long recognized that radiation transport theory is the foundation for the planning and analysis of X-ray (gamma-ray) radiation therapy and for imaging. In less common but appropriate occasions as an alternative to X-rays or…

Applied Physics · Physics 2021-04-20 Eric V. Steinfelds , Keith Andrew

Numerical simulations including magnetic fields have become important in many fields of astrophysics. Evolution of magnetic fields by the constrained transport algorithm preserves magnetic divergence to machine precision, and thus…

Astrophysics · Physics 2009-11-13 Jason Maron , Mordecai-Mark Mac Low , Jeffrey Oishi

Multichannel quantum defect theory (MQDT) has been widely applied to resonant and non-resonant scattering in a variety of atomic collision processes. In recent years, the method has been applied to cold collisions with considerable success,…

Atomic Physics · Physics 2015-06-22 Jisha Hazra , Brandon P. Ruzic , N. Balakrishnan , John L. Bohn

Motivated by the occurrence of "shattering" mass-loss observed in purely continuous fragmentation models, this work concerns the development and the mathematical analysis of a new class of hybrid discrete--continuous fragmentation models.…

Analysis of PDEs · Mathematics 2018-04-12 Graham Baird , Endre Süli
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