November 16th, 2021

лошадь, диаграмма, Фейнман

Состояние и перспективы физики нейтрино

Громадный обзор на 227 страниц.

Status and Perspectives of Neutrino Physics:

This review demonstrates the unique role of the neutrino by discussing in detail the physics of and with neutrinos. We deal with neutrino sources, neutrino oscillations, absolute masses, interactions, the possible existence of sterile neutrinos, and theoretical implications. In addition, synergies of neutrino physics with other research fields are found, and requirements to continue successful neutrino physics in the future, in terms of technological developments and adequate infrastructures, are stressed.
Comments: 227 pages; this review of the field of neutrino physics emerged from a report written by a panel on the request of IUPAP (International Union of Pure and Applied Physics). The mandate, the panel members and the report can be found on the web page of the panel at ht tps://www.this http URL
лошадь, диаграмма, Фейнман

О левитирующих лягушках, машинном обучении и эллиптических интегралах

Levitating frogs, machine learning and elliptic integrals:
M. Arrayás, J. L. Trueba, C. Uriarte
We present the calculation of the stability region of a perfect diamagnet levitated in a magnetic field created by a circular current loop. We make use of the machine learning technique of automatic differentiation to illustrate the calculations with the elliptic integrals involved.
лошадь, диаграмма, Фейнман

Новый метод вычисления интегралов в теории дифракции

Diffraction integral computation using sinc approximation:
Max Cubillos, Edwin Jimenez
We propose a method based on sinc series approximations for computing the Rayleigh-Sommerfeld and Fresnel diffraction integrals of optics. The diffraction integrals are given in terms of a convolution, and our proposed numerical approach is not only super-algebraically convergent, but it also satisfies an important property of the convolution -- namely, the preservation of bandwidth. Furthermore, the accuracy of the proposed method depends only on how well the source field is approximated; it is independent of wavelength, propagation distance, and observation plane discretization. In contrast, methods based on the fast Fourier transform (FFT), such as the angular spectrum method (ASM) and its variants, approximate the optical fields in the source and observation planes using Fourier series. We will show that the ASM introduces artificial periodic boundary conditions and violates the preservation of bandwidth property, resulting in limited accuracy which decreases for longer propagation distances. The sinc-based approach avoids both of these problems. Numerical results are presented for Gaussian beam propagation and circular aperture diffraction to demonstrate the high-order accuracy of the sinc method for both short-range and long-range propagation. For comparison, we also present numerical results obtained with the angular spectrum method.
Comments: 17 pages, 2 figures. Submitted for publication
лошадь, диаграмма, Фейнман

О маятниковых часах и стат.физике

Entropy of timekeeping in a mechanical clock:
David Ziemkiewicz
The dynamics of an unique type of clock mechanism known as grasshopper escapement is investigated with the aim of evaluating its accuracy in a noisy environment. It is demonstrated that the clock's precision scales linearly with the rate of its entropy production, consistently with recently reported results regarding nanoscale and quantum clocks. Moreover, it is shown that the inevitable force variations present in the mechanism can be modelled with a Maxwell-Boltzmann statistic. Finally, the function of clock error is compared with Brownian motion and its fractal-like properties are discussed. The numerical results are confirmed with experimental data.
Comments: 9 pages, 12 figures
Subjects: Applied Physics (; Classical Physics (physics.class-ph); Quantum Physics (quant-ph)