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The present study presents a comprehensive theoretical investigation of atom and asymmetric top molecule inelastic scattering based on the R-matrix formalism. The proposed methodology establishes a rigorous framework for treating inelastic…

The R-matrix method is a fully-quantum time-independent scattering method, used to simulate nuclear, electron-atom, electron-ion, electron-molecule scattering and more. Here, a novel R-matrix method, RmatReact, is presented as applied to…

Chemical Physics · Physics 2019-12-20 T. Rivlin , L. K. McKemmish , K. E. Spinlove , J. Tennyson

I present a direct boundary matching method (DBMM) for solving nuclear scattering problems using Lagrange-Legendre basis functions. This approach belongs to the family of bound-state techniques for the continuum, reformulating scattering…

Nuclear Theory · Physics 2025-12-09 Jin Lei

Package-X, a Mathematica package for the analytic computation of one-loop integrals dimensionally regulated near 4 spacetime dimensions is described. Package-X computes arbitrarily high rank tensor integrals with up to three propagators,…

High Energy Physics - Phenomenology · Physics 2015-12-01 Hiren H. Patel

A robust and general solver for the radial Schr\"odinger, Dirac, and Kohn--Sham equations is presented. The formulation admits general potentials and meshes: uniform, exponential, or other defined by nodal distribution and derivative…

Atomic Physics · Physics 2015-06-11 Ondřej Čertík , John E. Pask , Jiří Vackář

Electron-atom collisions in warm dense plasmas are crucial for astrophysics and controlled fusion research, where calculating short-range scattering matrices under screening plasma potentials is essential. While electron-neutral atom…

Atomic Physics · Physics 2026-01-28 Chao Wu , Wen Hao Xia , Yong Wu , Jun Yan , Ming Li , Jian Guo Wang , Xiang Gao

In coupled-channel models the poles of the scattering S-matrix are located on different Riemann sheets. Physical observables are affected mainly by poles closest to the physical region but sometimes shadow poles have considerable effect,…

Nuclear Theory · Physics 2018-02-14 R. M. Id Betan , A. T. Kruppa , T. Vertse

Low-energy nuclear interactions have been extensively studied in the framework of chiral effective field theory. The corresponding potentials have been worked out using dimensional regularization to evaluate ultraviolet divergent loop…

Nuclear Theory · Physics 2023-11-21 Hermann Krebs , Evgeny Epelbaum

Applications of relativistic light front dynamics to computing wave functions of heavy nuclei are reviewed. The motivation for this is the desire to find wave functions, expressed in terms of the plus-momentum variable, that simplify the…

Nuclear Theory · Physics 2011-08-11 Gerald A. Miller

We introduce a Python package that provides simply and unified access to a collection of datasets from fundamental physics research - including particle physics, astroparticle physics, and hadron- and nuclear physics - for supervised…

In this work, we focus on separable convex optimization problems with box constraints and a set of triangular linear constraints. The solution is given in closed-form as a function of some Lagrange multipliers that can be computed through…

Information Theory · Computer Science 2015-06-22 Antonio A. D'Amico , Luca Sanguinetti , Daniel P. Palomar

A Fortran program for the calculation of the ground state properties of axially deformed even-even nuclei in the relativistic framework is presented. In this relativistic mean field (RMF) approach a set of coupled differential equations…

Nuclear Theory · Physics 2009-10-30 P. Ring , Y. K. Gambhir , G. A. Lalazissis

This paper focuses on solving coupled problems of lumped parameter models. Such problems are of interest for the simulation of severe accidents in nuclear reactors~: these coarse-grained models allow for fast calculations for statistical…

Computational Engineering, Finance, and Science · Computer Science 2018-12-27 Louis Viot , Laurent Saas , Florian De Vuyst

The scattering of two charged strongly interacting particles is described on the basis of the P-matrix approach. In the P matrix, it is proposed to isolate explicitly the background term corresponding to purely Coulomb interaction, whereby…

Nuclear Theory · Physics 2007-05-23 V. A. Babenko , N. M. Petrov

There are three essential problems in computational relativistic chemistry: electrons moving at relativistic speeds, close lying states and dynamical correlation. Currently available quantum-chemical methods are capable of solving systems…

Chemical Physics · Physics 2020-05-08 Jan Brandejs , Jakub Višňák , Libor Veis , Maté Mihály , Örs Legeza , Jiří Pittner

Nuclear cross sections are basic inputs to any nuclear computation. Campaigns of experiments are fitted with the parametric R-matrix model of quantum nuclear interactions, and the resulting cross sections are documented - both point-wise…

Low-energy nuclear fusion reactions have been described using a dynamical coupled-channels density matrix method, based on the theory of open quantum systems. For the first time, this has been combined with an energy projection method,…

Nuclear Theory · Physics 2022-03-01 Iain Lee , Alexis Diaz-Torres

We propose a systematic T-matrix approach to solve few-body problems with s-wave contact interactions in ultracold atomic gases. The problem is generally reduced to a matrix equation expanded by a set of orthogonal molecular states,…

Quantum Gases · Physics 2015-03-17 Xiaoling Cui

A relativistic light front formulation of nuclear dynamics is applied to infinite nuclear matter. A hadronic meson-baryon Lagrangian, consistent with chiral symmetry, leads to a nuclear eigenvalue problem which is solved, including…

Nuclear Theory · Physics 2009-10-31 G. A. Miller , R. Machleidt

We employ the density matrix renormalization group (DMRG) and the wave function factorization method for the numerical solution of large scale nuclear structure problems. The DMRG exhibits an improved convergence for problems with realistic…

Nuclear Theory · Physics 2007-05-23 T. Papenbrock , D. J. Dean