November 17th, 2021

лошадь, диаграмма, Фейнман

О колебаниях пучка в накопительном кольце и поиске электрического дипольного момента частиц

Начинают они с классической теории.

Quantum mechanics of radiofrequency-driven coherent beam oscillations in storage rings: https://arxiv.org/abs/2111.08444
J. Slim, N.N. Nikolaev, F. Rathmann, A. Wirzba
Precision searches for the electric dipole moment of protons in storage ring experiments call for beam-position monitoring in the picometer range. We present the relevant fully quantum mechanical derivation of radiofrequency-driven collective oscillations of a beam in a storage ring.
Comments: 5 pages
лошадь, диаграмма, Фейнман

О вычислении сечения фотоионизации молекул

A complex Gaussian approach to molecular photoionization: https://arxiv.org/abs/2111.08637
Abdallah Ammar, Lorenzo Ugo Ancarani, Arnaud Leclerc
We develop and implement a Gaussian approach to calculate partial cross-sections and asymmetry parameters for molecular photoionization. Optimal sets of complex Gaussian-type orbitals (cGTOs) are first obtained by non-linear optimization, to best fit sets of Coulomb or distorted continuum wave functions for relevant orbital quantum numbers. This allows us to represent the radial wavefunction for the outgoing electron with accurate cGTO expansions. Within a time-independent partial wave approach, we show that all the necessary transition integrals become analytical, in both length and velocity gauges, thus facilitating the numerical evaluation of photoionization observables. Illustrative results, presented for NH3 and H2O within a one-active-electron monocentric model, validate numerically the proposed strategy based on a complex Gaussian representation of continuum states.
Comments: 32 pages, 1 table, 10 figures
лошадь, диаграмма, Фейнман

Снова учебно-методическое о выводе первого закона Кеплера без высшей математики

An algebra and trigonometry -based proof of Kepler's First Law: https://arxiv.org/abs/2111.08447
Akarsh Simha
An elementary proof of Kepler's first law, i.e. that bounded planetary orbits are elliptical, is derived without the use of calculus. The proof is similar in spirit to previous derivations, in that conservation laws are used to obtain an expression for the planetary orbit, which is then compared against an equation for the ellipse. However, we derive the equation that we match against, using trigonometry, from two well-known properties of the ellipse. Calculus is avoided altogether.
Comments: 7 pages, 2 figures
Journal reference: American Journal of Physics 89.11 (2021): 1009-1011

Comment on "An algebra and trigonometry-based proof of Kepler's first law" by Akarsh Simha: https://arxiv.org/abs/2111.11938
Manfred Bucher
The recent non-calculus proof of Kepler's first law succeeds because of an obscure, but valid property of the ellipse.
Comments: 3 pages

Поход по ссылкам показал, что этим баловался даже сам Унру:

Kepler's laws without calculus: https://arxiv.org/abs/1803.06770
William G Unruh
Kepler's laws are derived from the inverse square law without the use of calculus and are simplified over previous such derivations.
Comments: 11pages 3 figures --second version adds polygonal solution to equations. Third version cleans up the derivation of the polygonal ellipse

Впрочем, это я уже постил:)) По теме см. также тут.

И еще на ту же тему, но здесь, скорее, передирание Ландафшица без ссылок:

Elementary Solution of Kepler Problem (and a few other problems): https://arxiv.org/abs/2112.09064
M. Moriconi
We present a simple method to obtain the solution of a few orbital problems: the Kepler problem, the modified Kepler problem by the addition of an inverse square potential and linear force.
Comments: To appear in Revista Braileira de Ensino de Física
лошадь, диаграмма, Фейнман

Об электродинамике перспективных беспроводных технологий

Это сборник чего-то вроде коротких популярных докладов с обширной библиографией.

Smart Radio Environments: https://arxiv.org/abs/2111.08676

This Roadmap takes the reader on a journey through the research in electromagnetic wave propagation control via reconfigurable intelligent surfaces. Meta-surface modelling and design methods are reviewed along with physical realisation techniques. Several wireless applications are discussed, including beam-forming, focusing, imaging, localisation, and sensing, some rooted in novel architectures for future mobile communications networks towards 6G.
Comments: 55 pages, 22 figures, submitted to Reviews of Electromagnetics
лошадь, диаграмма, Фейнман

Как ядерная физика может помочь улучшить позитронно-эмиссионную томографию (ПЭТ)

Radioactive nuclei for β+γ PET and theranostics: selected candidates: https://arxiv.org/abs/2111.08659
Tomasz Matulewicz
PET is an established medical diagnostic imaging method. Continuous improvements are aimed at refining image reconstruction, reducing the amount of radioactive tracer and combining with targeted therapy. TOF-PET provides the localization of the tracer through improved time resolution, nuclear physics may contribute to this goal via selection of radioactive nuclei emitting additional γ-rays. This additional radiation, when properly detected, localizes the decay of the tracer at the line of response determined by two detected 511 keV quanta. Selected candidates are presented. Some are particularly interesting, as they are strong candidates for theranostic applications.
Comments: 6 pages, 4 figures; accepted for publication in Bio-Algorithms and Med-Systems. The final publication is available at this https URL