June 2nd, 2021

лошадь, диаграмма, Фейнман

Уравнение Липпмана-Швингера, и прочее, и прочее...

Тут много всякого потенциально полезного наворочено, надо бы почитать...

Accelerating Nucleon-Nucleon Scattering Calculations: https://arxiv.org/abs/2106.00454
Sean B. S. Miller, Andreas Ekström, Christian Forssén
In this paper we analyse the efficiency, precision, and accuracy of computing elastic nucleon-nucleon (NN) scattering amplitudes with the wave-packet continuum discretisation method (WPCD). This method provides approximate scattering solutions at multiple scattering energies simultaneously. We therefore utilise a graphics processing unit (GPU) to explore the benefits of this inherent parallelism. From a theoretical perspective, the WPCD method promises a speedup compared to a standard matrix-inversion method. We use the chiral NNLOopt interaction to demonstrate that WPCD enables efficient computation of NN scattering amplitudes provided one can tolerate an averaged method error of 1−5 mb in the total cross section. For scattering energies ≳40 MeV, in the laboratory frame of reference, we find a much smaller method error of ≲1 mb. By increasing the number of wave-packets we can further reduce the overall method error. However, the parallel leverage of the WPCD method will be offset by the increased size of the resulting discretisation mesh. In practice, the GPU implementation is only useful for matrices that fit in the fast on-chip shared memory. Nevertheless, we find that WPCD is a promising method for computationally efficient, statistical analyses of EFT nuclear interactions, where we can utilise Bayesian inference methods to incorporate relevant uncertainties.
Comments: 17 pages, 9 figures
лошадь, диаграмма, Фейнман

А можно ли создать ядро, дико перегруженное нейтронами, подобное нейтронной звезде?

Когда-то мне уже что-то встречалось из этой серии "Переписывая учебники ядерной физики"...

The extremes of neutron richness: https://arxiv.org/abs/2106.00516
F. Miguel Marqués
A neutron star is pictured as a gigantic nucleus overwhelmed by the number of neutrons, unlike real atomic nuclei, that have a similar number of neutrons and protons. Is this true? What if we could find, or create nuclei without protons? How far can we go in neutron richness? Our common sense tells us that these neutral nuclei should not exist, but if they do they would change our knowledge on neutron stars, on the properties of nuclei in general, and ultimately on the nucleon-nucleon interaction itself, the building block of matter. This huge potential impact has pushed some ambitious nuclear physicists to search for them since the 1960s. The first positive hints appeared only in the XXI century, and nowadays several collaborations are trying to corner these weird objects and give a definite answer to this crucial question. In this \edit{review} we will go through this fascinating quest, that started with humble experiments and has now reached a stage of ambitious and sophisticated projects, both in experiment and theory.
Comments: 21 pages, 15 figures, lecture given at the Third Pisa Summer School, "Rewriting Nuclear Physics Textbooks: one more step forward", University of Pisa (Italy), July 22-26, 2019
лошадь, диаграмма, Фейнман

Плазменная медицина: краткое введение

Plasma Medicine: A Brief Introduction: https://arxiv.org/abs/2106.00595
Mounir Laroussi
This mini review is to introduce the readers of Plasma to the field of plasma medicine. This is a multidisciplinary field of research at the intersection of physics, engineering, biology and medicine. Plasma medicine is only about two decades old, but the research community active in this emerging field has grown tremendously in the last few years. Today, research is being conducted on a number of applications including wound healing and cancer treatment. Although a lot of knowledge has been created and our understanding of the fundamental mechanisms that play important roles in the interaction between low temperature plasma and biological cells and tissues has greatly expanded, much remains to be done to get a thorough and detailed picture of all the physical and biochemical processes that enter into play.