January 14th, 2021

лошадь, диаграмма, Фейнман

Автор утверждает, что это самый простой вывод законов Ньютона из законов Кеплера...

...для тех, у кого есть под рукой Градштейн и Рыжик и Уиттекер-Ватсон:)))

From Kepler's Laws to Newtonian Motion and the Direction Angle of Hamilton's Hodograph: https://arxiv.org/abs/2101.05041
Klaus Huber
In this contribution it is shown that the path from Kepler's results to Newtonian motion can be remarkably short and simple. Following this path we also give a straight forward computation of the direction angle of Hamilton's Hodograph. Then we show how the speed as function of the direction angle can be expressed and inverted elegantly using elliptic functions.
Comments: 6 pages, 3 figures
лошадь, диаграмма, Фейнман

И снова о движении спина

Electric dipole moment in storage ring experiments: https://arxiv.org/abs/2101.05064
Peter I Porshnev
The measurement of electric dipole moment in storage rings can potentially exceed the sensitivity of tests with neutral systems. The spin dynamics under such conditions is described by the Bargmann-Michel-Telegdi equation. It can be derived in the semiclassical approximation under several assumptions one of which is the zero pseudoscalar bilinear. However, many promising extensions to the standard model consider scalar-pseudoscalar couplings which assume nonzero electron pseudoscalar. We re-derive the spin precession equation under conditions that do not assume that pseudoscalar is zero. It leads to a correction term that might be required for matching the storage ring measurements with QFT evaluations.
Comments: Accepted by Physica Scripta (Particles, fields, and nuclear physics)