approximation theory
41Time-dependent density functional theory — (TDDFT) is a quantum mechanical method used inphysics and chemistry to investigate the proprieties of many body systems beyond the ground statestructure. It s an extension of density functional theory (DFT) to the time dependent domain asa method …
42Gans theory — or Mie Gans theory is the extension of Mie theory for the case of spheroidal particles. It gives the scattering characteristics of both oblate and prolate spheroidal particles much smaller than the excitation wavelength.Since it is a solution of… …
43M-theory — For a generally accessible and less technical introduction to the topic, see Introduction to M theory. String theory …
44High frequency approximation — A high frequency approximation (or high energy approximation ) for scattering or other wave propagation problems, in physics or engineering, is an approximation whose accuracy increases with the size of features on the scatterer or medium… …
45Local-density approximation — The local density approximation (LDA) is an approximation of the exchange correlation (XC) energy functional in density functional theory (DFT) by taking the XC energy of an electron in a homogeneous electron gas of a density equal to the density …
46Info-gap decision theory — is a non probabilistic decision theory that seeks to optimize robustness to failure – or opportuneness for windfall – under severe uncertainty,[1][2] in particular applying sensitivity analysis of the stability radius type[3] to perturbations in… …
47Théorème de Hurwitz (approximation diophantienne) — Pour les articles homonymes, voir Théorème de Hurwitz. En théorie des nombres, le théorème de Hurwitz sur les approximations diophantiennes, établi en 1891 par Adolf Hurwitz, dit que pour tout nombre irrationnel x, il existe une infinité de… …
48Perturbation theory — This article describes perturbation theory as a general mathematical method. For perturbation theory as applied to quantum mechanics, see perturbation theory (quantum mechanics). Perturbation theory comprises mathematical methods that are used to …
49Common integrals in quantum field theory — There are common integrals in quantum field theory that appear repeatedly.[1] These integrals are all variations and generalizations of gaussian integrals to the complex plane and to multiple dimensions. Other integrals can be approximated by… …
50Analytic number theory — In mathematics, analytic number theory is a branch of number theory that uses methods from mathematical analysis to solve number theoretical problems. [Page 7 of Apostol 1976] It is often said to have begun with Dirichlet s introduction of… …
