**Perturbation 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 … Wikipedia

**perturbation theory** — trikdymų teorija statusas T sritis fizika atitikmenys: angl. disturbation theory; perturbation theory vok. Störungstheorie, f rus. теория возмущений, f pranc. théorie des perturbations, f … Fizikos terminų žodynas

**Perturbation 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 … Wikipedia

**Møller–Plesset perturbation theory** — Electronic structure methods Tight binding Nearly free electron model Hartree–Fock method Modern valence bond Generalized valence bond Møller–Plesset perturbation th … Wikipedia

**Møller-Plesset perturbation theory** — (MP) is one of several quantum chemistry post Hartree Fock ab initio methods in the field of computational chemistry. It improves on the Hartree Fock method by adding electron correlation effects by means of Rayleigh Schrödinger perturbation… … Wikipedia

**Cosmological perturbation theory** — See also: structure formation , cosmic microwave background radiation , and general relativity In physical cosmology, cosmological perturbation theory is the theory by which the evolution of structure is understood in the big bang model. It… … Wikipedia

**K·p perturbation theory** — In solid state physics, k·p perturbation theory is an approximation scheme for calculating the band structure (particularly effective mass) and optical properties of crystalline solids. It is pronounced k dot p , and is also called the k·p method … Wikipedia

**n-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… … Wikipedia

**N-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… … Wikipedia

**Chiral perturbation theory** — (ChPT) is an effective field theory constructed with a Lagrangian consistent with the (approximate) chiral symmetry of quantum chromodynamics (QCD), as well as the other symmetries of parity and charge conjugation. ChPT is a theory which allows… … Wikipedia