perturbation theory


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perturbation theory

[‚pər·tər′bā·shən ‚thē·ə·rē]
(mathematics)
The study of the solutions of differential and partial differential equations from the viewpoint of perturbation of solutions.
(physics)
The theory of obtaining approximate solutions to the equations of motion of a physical system when these equations differ by a small amount from equations which can be solved exactly.
References in periodicals archive ?
Borasoy [14] has shown that [eta]' can also be included in baryon chiral perturbation theory in a systematic way.
The focus of this project is to merge Lie perturbation theory and DA and TM techniques with the goal of applying the resulting methodology to practical problems in SSA.
I will model the inspiral part of the orbital evolution by using black hole perturbation theory, an approximation method in general relativity.
They write for graduate students of applied mathematics, physics, and engineering and for bold undergraduates with a knowledge of partial differential equations, perturbation theory, and elementary physics.
Improvements are expected also by studying others nonperturbative QCD effects, as renormalons, associated to divergences of the perturbation theory, or possible mechanisms for confinement, as monopole condensation.
Some topics have been omitted and placed on the web site; others, such as the Wigner quasi-probability distribution, time- dependent perturbation theory, and timescales in bound state systems, are new.
i) The first one is the study of string thermodynamics at high temperature well string perturbation theory breaks down.
They describe geometric, algebraic, topological and analytic properties of invariant subspaces that serve as foundations for linear systems theory and include a treatment of analytic perturbation theory for matrix functions.
The results of this study will facilitate a better understanding of a quantum field theory, such as QCD, beyond naive perturbation theory. Today, exploring QCD under extreme conditions, such as at high energy/density, is more important than ever due to its relevance for the LHC and future collider programs.
of Geneva) covers Lorentz and Poincare symmetries in quantum field theory, classical field theory, quantization of free fields, perturbation theory and Feynman diagrams, cross-section and decay rates, quantum electrodynamics, the low-energy limit of the electroweak theory, path integral quantization, non- abelian gauge theories, and spontaneous symmetry breaking.
Algebraic analysis of singular perturbation theory.
The papers include such topics as: Lie group integrators, geometric integrators, and exponential integrators; symbolic computation and solutions of ordinary differential equations, partial differential equations and differential-difference equations; symmetry preserving discretization of ordinary and partial differential equations; discrete and finite Fourier transforms and data processing; boundary layer perturbation theory and its symmetry respecting discretization; discrete symmetries of difference and differential difference equations; numerical methods for treating rapid oscillations; orthogonal polynomials related to Pade approximations; and applications in biophysics and physics.