In mathematics, variational perturbation theory (VPT) is a mathematical method to convert divergent power series in a small expansion parameter, say s...

In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact...

In quantum mechanics, perturbation theory is a set of approximation schemes directly related to mathematical perturbation for describing a complicated...

Møller–Plesset perturbation theory (MP) is one of several quantum chemistry post-Hartree–Fock ab initio methods in the field of computational chemistry...

numerically the critical exponents, and variational perturbation theory, which converts divergent perturbation expansions into convergent strong-coupling...

The calculus of variations (or variational calculus) is a field of mathematical analysis that uses variations, which are small changes in functions and...

perturbation expansions into convergent strong-coupling expansions (variational perturbation theory) and, as a consequence, to the most accurate determination...

strong-coupling ones. This so-called variational perturbation theory yields at present the most accurate theory of critical exponents observable close...

In mathematics, an eigenvalue perturbation problem is that of finding the eigenvectors and eigenvalues of a system A x = λ x {\displaystyle Ax=\lambda...

experimental value of α agrees with theoretical predictions based on variational perturbation theory. For 0 < α < 1, the heat capacity diverges at the transition...

density contributes a term in the gradient of the density. In a perturbation theory approach the direct correlation function is given by the sum of the...

equation into the Schrödinger equation and applying the variational principle. The variational principle is a mathematical technique used in quantum mechanics...

theory — Perturbation theory — Potential theory — Probability theory — Ramsey theory — Rational choice theory — Representation theory — Ring theory —...

Automata theory is the study of abstract machines and automata, as well as the computational problems that can be solved using them. It is a theory in theoretical...

motions under small perturbations. The theorem partly resolves the small-divisor problem that arises in the perturbation theory of classical mechanics...

nonadiabatic transition state theory (NA-TST). Using vibrational perturbation theory, effects such as tunnelling and variational effects can be accounted for...

function. One of these approaches, Møller–Plesset perturbation theory, treats correlation as a perturbation of the Fock operator. Others expand the true multi-electron...

In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massive...

Probability theory or probability calculus is the branch of mathematics concerned with probability. Although there are several different probability interpretations...

(QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a physics...

Decision theory or the theory of rational choice is a branch of probability, economics, and analytic philosophy that uses expected utility and probability...

physics, but was hindered by the extensive use of perturbation theory, which prevented the theory from succeeding in strongly correlated systems. Conformal...

inflationary potentials, as long as the theory can be studied through perturbation theory. Linde proposed a theory known as chaotic inflation in which he...

In physics and probability theory, Mean-field theory (MFT) or Self-consistent field theory studies the behavior of high-dimensional random (stochastic)...

Schwinger's quantum action principle is a variational approach to quantum mechanics and quantum field theory. This theory was introduced by Julian Schwinger...

renormalization of the theory. When the running coupling of the theory is small enough, then all required quantities may be computed in perturbation theory. Quantization...

Look up variation in Wiktionary, the free dictionary. Variation or Variations may refer to: Variation (astronomy), any perturbation of the mean motion...

Coding theory is the study of the properties of codes and their respective fitness for specific applications. Codes are used for data compression, cryptography...

metric includes four scalar perturbations, two vector perturbations, and one tensor perturbation. Only the scalar perturbations are significant: the vectors...

Quantum field theory Classical unified field theories Variational methods in general relativity Higgs field (classical) Lagrangian (field theory) Hamiltonian...