Search results
Results from the WOW.Com Content Network
The Schwinger–Dyson equations (SDEs) or Dyson–Schwinger equations, named after Julian Schwinger and Freeman Dyson, are general relations between correlation functions in quantum field theories (QFTs).
The technique of renormalization, suggested by Ernst Stueckelberg and Hans Bethe and implemented by Dyson, Feynman, Schwinger, and Tomonaga compensates for this effect and eliminates the troublesome infinities. After renormalization, calculations using Feynman diagrams match experimental results with very high accuracy.
In scattering theory, a part of mathematical physics, the Dyson series, formulated by Freeman Dyson, is a perturbative expansion of the time evolution operator in the interaction picture. Each term can be represented by a sum of Feynman diagrams .
Based on Bethe's intuition and fundamental papers on the subject by Shin'ichirō Tomonaga, [16] Julian Schwinger, [17] [18] Richard Feynman [1] [19] [20] and Freeman Dyson, [21] [22] it was finally possible to produce fully covariant formulations that were finite at any order in a perturbation series of quantum electrodynamics.
The starting point for the derivation of the Bethe–Salpeter equation is the two-particle (or four point) Dyson equation = + in momentum space, where "G" is the two-particle Green function | | , "S" are the free propagators and "K" is an interaction kernel, which contains all possible interactions between the two particles.
By utilizing the interaction picture, one can use time-dependent perturbation theory to find the effect of H 1,I, [15]: 355ff e.g., in the derivation of Fermi's golden rule, [15]: 359–363 or the Dyson series [15]: 355–357 in quantum field theory: in 1947, Shin'ichirō Tomonaga and Julian Schwinger appreciated that covariant perturbation ...
Quantum field theory originated in the 1920s from the problem of creating a quantum mechanical theory of the electromagnetic field.In particular, de Broglie in 1924 introduced the idea of a wave description of elementary systems in the following way: "we proceed in this work from the assumption of the existence of a certain periodic phenomenon of a yet to be determined character, which is to ...
In Schwinger's approach, the action principle is targeted towards quantum mechanics. The action becomes a quantum action , i.e. an operator, S {\displaystyle S} . Although it is superficially different from the path integral formulation where the action is a classical function, the modern formulation of the two formalisms are identical.