October 1st, 2019

лошадь, диаграмма, Фейнман

Обзорчик о массе нуклона

Insights into the Origin of Mass: https://arxiv.org/abs/1909.12832

tomic nuclei are the core of everything we can see. At the first level of approximation, their atomic weights are simply the sum of the masses of all the nucleons they contain. Each nucleon has a mass mN≈1GeV, i.e. approximately 2000-times the electron mass. The Higgs boson produces the latter, but what produces the nucleon mass? This is the crux: the vast bulk of the mass of a nucleon is lodged with the energy needed to hold quarks together inside it; and that is supposed to be explained by quantum chromodynamics (QCD), the strong-interaction piece within the Standard Model. This contribution canvasses the potential for a coherent effort in QCD phenomenology and theory, coupled with experiments at existing and planned facilities, to reveal the origin and distribution of mass by focusing on the properties of the strong-interaction Nambu-Goldstone modes. Key experiments are approved at JLab 12; planned with COMPASS++/AMBER at CERN; and could deliver far-reaching insights by exploiting the unique capabilities foreseen at an electron ion collider.
Comments: 9 pages, 4 figures. Summary of a plenary presentation at "INPC 2019 - 27th International Nuclear Physics Conference", Glasgow, UK, 29 July to 2
лошадь, диаграмма, Фейнман

Задачка от Зураба Силагадзе с разбором и продолжением

Maximum attainable energy at a fixed frequency cyclotron: https://arxiv.org/abs/1909.13440

We consider a problem of finding the maximum attainable energy at a cyclotron as an exercise in the introductory relativity course and comment on some subtle points of the solution.
Comments: 7 pages, revtex4, to be published in Eur. J. Phys
лошадь, диаграмма, Фейнман

Радиофизическая задачка

Free space transmission lines in receiving antenna operation: https://arxiv.org/abs/1909.13665

This work derives exact expressions for the voltage and current induced into a two conductors non isolated transmission lines by an incident plane wave. The methodology is to use the transmission line radiating properties to derive scattering matrices and make use of reciprocity to derive the response to the incident wave. The analysis is in the frequency domain and it considers transmission lines of any small electric cross section, incident by a plane wave from any incident direction and any polarisation. The analytic results are validated by successful comparison with ANSYS commercial software simulation results, and compatible with other published results.
Comments: 17 pages, 30 figures
лошадь, диаграмма, Фейнман

Как работает метод Монте-Карло?

Автор предлагает экспериментировать, разрываю бумагу на мелкие клочки:

How does the Monte Carlo method work?: https://arxiv.org/abs/1909.13212

The paper describes the practical work for students visually clarifying the mechanism of the Monte Carlo method applying to approximating the value of Pi. Considering a traditional quadrant (circular sector) inscribed in a square, here we demonstrate the original algorithm for generating random points on the paper: you should arbitrarily tear up a paper blank to small pieces (the first experiment). By the similar way the second experiment (with a preliminary staining procedure by bright colors) can be used to prove the quadratic dependence of the area of a circle on its radius. Manipulations with tearing up a paper as a random sampling algorithm can be applied for solving other teaching problems in physics.
Comments: 17 pages, 6 figures, 2 tables, 2 appendixes
лошадь, диаграмма, Фейнман

Утки балдеют на мелководье

Снято 14 августа. Семья диких уток (мама и 8 подросших детей) подплыли к пляжику и там наслаждались жизнью, меня подпустили совсем близко. Эту фотосессию я буду публиковать частями, и очень-очень долго:))


DSC_0101_obr.jpg © qedqed.iMGSRC.RU


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