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In this work, we investigate a novel approach for the simulation of two-dimensional, brittle, quasi-static fracture problems based on a shape optimization approach. In contrast to the commonly-used phase-field approach, this proposed…

Optimization and Control · Mathematics 2025-07-28 Tim Suchan , Winnifried Wollner , Kathrin Welker

Solutions to the phonon Boltzmann transport equation under the relaxation-time approximation (RTA) are fundamentally limited in that they do not account for the off-diagonal elements of the scattering matrix, which encode intermode energy…

Computational Physics · Physics 2026-05-25 Y. Sungtaek Ju

Fast and accurate predictions of the spatiotemporal distributions of temperature are crucial to the multi-scale thermal management and safe operation of microelectronic devices. To realize it, an efficient semi-implicit Lax-Wendroff kinetic…

Computational Physics · Physics 2024-12-04 Shuang Peng , Songze Chen , Hong Liang , Chuang Zhang

We construct transported PDEs on self-similar fractal domains from reference equations posed on the unit interval, and derive explicit self-similar interacting particle systems that approximate the resulting dynamics. The construction…

Analysis of PDEs · Mathematics 2026-04-28 Georgi Medvedev , Emmanuel Trélat

We study properties of neutrino transfer in a remnant of neutron star merger, consisting of a massive neutron star and a surrounding torus. We perform numerical simulations of the neutrino transfer by solving the Boltzmann equation with…

High Energy Astrophysical Phenomena · Physics 2021-02-23 Kohsuke Sumiyoshi , Sho Fujibayashi , Yuichiro Sekiguchi , Masaru Shibata

We discuss mechanisms related to isospin transport in central collisions between neutron-rich systems at Fermi energies. A fully consistent study of the isospin distillation and expansion dynamics in two-component systems is presented in…

Nuclear Theory · Physics 2009-01-08 M. Colonna , V. Baran , M. Di Toro , H. H. Wolter

Neutrino-neutrino scattering could have a large secret component that would turn neutrinos within a supernova (SN) core into a self-coupled fluid. Neutrino transport within the SN core, emission from its surface, expansion into space, and…

High Energy Physics - Phenomenology · Physics 2024-01-12 Damiano F. G. Fiorillo , Georg Raffelt , Edoardo Vitagliano

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

A three-body semiclassical model is proposed to describe the nucleon transfer and emission reactions in a heavy-ion collision. In this model the two heavy particles, i.e. nuclear cores A$_1(Z_{A_1}, M_{A_1})$ and A$_2(Z_{A_2}, M_{A_2})$,…

Nuclear Theory · Physics 2015-06-16 Renat A. Sultanov , D. Guster

We perform an ab initio computational investigation of the electronic and thermoelectric transport properties of one of the best performance half-Heusler (HH) alloys, NbFeSb. We use Boltzmann Transport equation while taking into account the…

Materials Science · Physics 2025-10-28 Bhawna Sahni , Yao Zhao , Zhen Li , Rajeev Dutt , Patrizio Graziosi , Neophytos Neophytou

We test approximate approaches to solving a neutrino transport problem that presents itself in the analysis of some accretion-disk models. Approximation #1 consists of replacing the full, angular- dependent, distribution function by a…

Astrophysics · Physics 2016-08-30 R. F. Sawyer

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 characterize the particle transport, particle loss, and nonequilibrium steady states in a dissipative one-dimensional lattice connected to reservoirs at both ends. The free-fermion reservoirs are fixed at different chemical potentials,…

Quantum Gases · Physics 2023-03-27 A. -M. Visuri , T. Giamarchi , C. Kollath

Optimal transport problems pose many challenges when considering their numerical treatment. We investigate the solution of a PDE-constrained optimisation problem subject to a particular transport equation arising from the modelling of image…

Numerical Analysis · Mathematics 2018-01-15 Roland Herzog , John W. Pearson , Martin Stoll

Mesoscopic numerical simulation has become an important tool in thermal management and energy harvesting at the micro/nano scale, where the Fourier's law failed. However, it is not easy to efficiently solve the phonon Boltzmann transport…

Computational Physics · Physics 2022-12-13 Chuang Zhang , Samuel Huberman , Xinliang Song , Jin Zhao , Songze Chen , Lei Wu

We propose a Forward-Backward Truncated-Newton method (FBTN) for minimizing the sum of two convex functions, one of which smooth. Unlike other proximal Newton methods, our approach does not involve the employment of variable metrics, but is…

Optimization and Control · Mathematics 2019-11-11 Andreas Themelis , Masoud Ahookhosh , Panagiotis Patrinos

The mass and total kinetic energy distributions of the fission fragments in the fission of even-even isotopes of superheavy elements from Hs (Z=108) to Og (Z=118) are estimated using a pre-scission point model. We restrict to nuclei for…

Nuclear Theory · Physics 2019-06-19 N. Carjan , F. A. Ivanyuk , Yu. Ts. Oganessian

We review the calculations of the kinetic coefficients (thermal conductivity, shear viscosity, momentum transfer rates) of the neutron star core matter within the framework of the Landau Fermi-liquid theory. We restrict ourselves to the…

Nuclear Theory · Physics 2022-03-23 Peter Shternin , Dmitry Ofengeim

One of the major difficulties encountered in modeling core collapse supernovae is obtaining an accurate description of the transport of neutrinos through the collapsed stellar core. The behavior of the neutrino distribution function…

Astrophysics · Physics 2007-05-23 F. Douglas Swesty

We present the newly developed stochastic model of the galactic cosmic ray (GCR) particles transport in the heliosphere. Mathematically Parker transport equation (PTE) describing non-stationary transport of charged particles in the…

Solar and Stellar Astrophysics · Physics 2015-09-23 A. Wawrzynczak , R. Modzelewska , A. Gil