лошадь, диаграмма, Фейнман

Коллекция моих книг

лошадь, диаграмма, Фейнман


Мои уважаемые френды (среди них особенно уважаемая merrilymerrily) интересуются: а как я воспользовался рецептами домашнего хлеба, которые я у них когда-то просил? Спешу ответить: самым наилучшим образом! Да только вот оказалось, что сфотографировать домашний хлеб не легче, чем ласку в зимне-весенней шубе, уж больно редкий это зверь, можно сказать, короткоживущий:) Съедается, как правило, быстрее, чем успеваешь сбегать за фотоаппаратом:)) Но на днях я его таки подловил:

20191204_212630_obr.jpg © qedqed.iMGSRC.RU

На основе рецепта уважаемого voldemarych :) Пользуясь случаем, еще раз благодарю всех френдов за рецепты и ценные обсуждения!
лошадь, диаграмма, Фейнман

Нахождение собственных значений с помощью функций Грина и уравнения Липпмана-Швингера

Всегда воспринимал уравнение Липпмана-Швингера как что-то чисто символическое, а тут - надо же! Очень интересно и, возможно, полезно:

Calculation of eigenvalues by Greens-functions and the Lippmann-Schwinger equation: https://arxiv.org/abs/1902.01624

We calculate eigenvalues of one-dimensional quantum-systems by the exact numerical solution of the Lippmann-Schwinger equation, analogous to the scattering problem. To illustrate our method, we treat elementary problems: the harmonic and quartic oscillator, a symmetric and a skew double-well potential, and potentials with finite and infinite depth. Furthermore, we show how our method can be used for eigenvalue-engineering.
Comments: 8 pages, 6 figures
лошадь, диаграмма, Фейнман

Исследование резонанса при ручном вздрючивании игрушечной пружины

Manually driven harmonic oscillator: https://arxiv.org/abs/1911.12639

Oscillations and resonance are essential topics in physics that can be explored theoretically and experimentally in the classroom or teaching laboratory environments. However, one of the main challenges concerning the experimental study of resonance phenomena via forced oscillations is the control of the oscillation frequency, which demands an electronic circuit or a fine tuned coupled mechanical system. In this work, we demonstrate that, in what concerns the physics teaching, such demanding accessories are not necessary. The forced oscillations can be implemented by the teacher's hand guided by an oscillating circle displayed in a web application loaded in a smartphone. The oscillations are applied to an ordinary spiral toy. Qualitative, as well quantitative, proposals are explored in this work with excellent results.
лошадь, диаграмма, Фейнман

Квантовая и классическая динамика в фазовом пространстве лазера на свободных электронах

Quantum and classical phase-space dynamics of a free-electron laser: https://arxiv.org/abs/1911.12584

In a quantum mechanical description of the free-electron laser (FEL) the electrons jump on discrete momentum ladders, while they follow continuous trajectories according to the classical description. In order to observe the transition from quantum to classical dynamics, it is not sufficient that many momentum levels are involved. Only if additionally the initial momentum spread of the electron beam is larger than the quantum mechanical recoil, caused by the emission and absorption of photons, the quantum dynamics in phase space resembles the classical one. Beyond these criteria, quantum signatures of averaged quantities like the FEL gain might be washed out.
лошадь, диаграмма, Фейнман


Goldstone Equivalence and High Energy Electroweak Physics: https://arxiv.org/abs/1911.12366

The transition between the broken and unbroken phases of massive gauge theories, namely the rearrangement of longitudinal and Goldstone degrees of freedom that occurs at high energy, is not manifestly smooth in the standard formalism. The lack of smoothness concretely shows up as an anomalous growth with energy of the longitudinal polarization vectors, as they emerge in Feynman rules both for real on-shell external particles and for virtual particles from the decomposition of the gauge field propagator. This makes the characterization of Feynman amplitudes in the high-energy limit quite cumbersome, which in turn poses peculiar challenges in the study of Electroweak processes at energies much above the Electroweak scale. We develop a Lorentz-covariant formalism where polarization vectors are well-behaved and, consequently, energy power-counting is manifest at the level of individual Feynman diagrams. This allows us to prove the validity of the Effective W Approximation and, more generally, the factorization of collinear emissions and to compute the corresponding splitting functions at the tree-level order. Our formalism applies at all orders in perturbation theory, for arbitrary gauge groups and generic linear gauge-fixing functionals. It can be used to simplify Standard Model loop calculations by performing the high-energy expansion directly on the Feynman diagrams. This is illustrated by computing the radiative corrections to the decay of the top quark.
Comments: 50 pages + appendices, 7 figures