November 15th, 2021

лошадь, диаграмма, Фейнман

Пакет для Математики по работе с тензорами и спинорами

Сам я Математикой не пользуюсь, но пусть будет.

SimpleTensor -- a user-friendly Mathematica package for elementary tensor and differential-geometric calculations: https://arxiv.org/abs/2111.06718
D. O. Rybalka
In this paper we present a short overview of the new Wolfram Mathematica package intended for elementary "in-basis" tensor and differential-geometric calculations. In contrast to alternatives our package is designed to be easy-to-use, short, all-purpose, and hackable. It supports tensor contractions using Einstein notation, transformations between different bases, tensor derivative operator, expansion in basis vectors and forms, exterior derivative, and interior product.
Comments: 13 pages
лошадь, диаграмма, Фейнман

О прохождении электронов и рентгеновского излучения через кристаллы и его моделировании

Хорошее введение.

turboEELS -- A code for the simulation of the electron energy loss and inelastic X-ray scattering spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory: https://arxiv.org/abs/2111.06623
Iurii Timrov, Nathalie Vast, Ralph Gebauer, Stefano Baroni
We introduce turboEELS, an implementation of the Liouville-Lanczos approach to linearized time-dependent density-functional theory, designed to simulate electron energy loss and inelastic X-ray scattering spectra in periodic solids. turboEELS is open-source software distributed under the terms of the GPL as a component of Quantum ESPRESSO. As with other components, turboEELS is optimized to run on a variety of different platforms, from laptops to massively parallel architectures, using native mathematical libraries (LAPACK and FFTW) and a hierarchy of custom parallelization layers built on top of MPI.
лошадь, диаграмма, Фейнман

Очередная домашняя лаба с использованием смартфона

Determination of the refractive index of water and glass using smartphone cameras by estimating the apparent depth of an object: https://arxiv.org/abs/2111.06735
Sanjoy Kumar Pal, Soumen sarkar, Surajit Chakrabarti
A smartphone camera can be used for measuring the width and distance of an object by taking its photograph. The focal length of the camera lens can be determined very accurately by finding the image width of an object on the camera sensor to micron level accuracy. The level of accuracy achieved with the help of camera sensors, allows us to determine the refractive index of water upto four significant digits by finding the apparent depth of an object immersed in it. We have also measured the refractive index of glass by the same method, using three glass slides of different thicknesses, the smallest being 1.2 mm.
Comments: 12 pages, 1 figure