(the formal perturbation procedure known as the)
1Perturbation theory (quantum mechanics) — In quantum mechanics, perturbation theory is a set of approximation schemes directly related to mathematical perturbation for describing a complicated quantum system in terms of a simpler one. The idea is to start with a simple system for which a …
2N-Electron Valence state Perturbation Theory — In quantum chemistry, N Electron Valence state Perturbation Theory (NEVPT) is a perturbative treatment applicable to multireference CASCI type wavefunctions. It can be considered as a generalization of the well known second order Møller Plesset… …
3n-electron valence state perturbation theory — In quantum chemistry, n electron valence state perturbation theory (NEVPT) is a perturbative treatment applicable to multireference CASCI type wavefunctions. It can be considered as a generalization of the well known second order Møller Plesset… …
4electromagnetic radiation — Physics. radiation consisting of electromagnetic waves, including radio waves, infrared, visible light, ultraviolet, x rays, and gamma rays. [1950 55] * * * Energy propagated through free space or through a material medium in the form of… …
5BRST quantization — In theoretical physics, BRST quantization (where the BRST refers to Becchi, Rouet, Stora and Tyutin) is a relatively rigorous mathematical approach to quantizing a field theory with a gauge symmetry. Quantization rules in earlier QFT frameworks… …
6physical science, principles of — Introduction the procedures and concepts employed by those who study the inorganic world. physical science, like all the natural sciences, is concerned with describing and relating to one another those experiences of the surrounding… …
7Charles Sanders Peirce —  B …
8Orbifold — This terminology should not be blamed on me. It was obtained by a democratic process in my course of 1976 77. An orbifold is something with many folds; unfortunately, the word “manifold” already has a different definition. I tried “foldamani”,… …
9Egypt — /ee jipt/, n. 1. Arab Republic of. a republic in NE Africa. 64,791,891; 386,198 sq. mi. (1,000,252 sq. km). Cap.: Cairo. Arabic, Misr. Formerly (1958 71), United Arab Republic. 2. an ancient kingdom in NE Africa: divided into the Nile Delta… …
10Nikolay Bogolyubov — For the actor, see Nikolay Bogolyubov (actor). Nikolay Nikolaevich Bogolyubov Born 21 August 1909( …
- 1
- 2
