The method of investigating solutions of equations representing physical systems, especially quantum systems, by relating them by means of perturbations to those of similar but simpler systems which can be solved directly.
Origin
1920s; earliest use found in Proceedings of the Royal Society of London.
Definition of perturbation theory in US English:
perturbation theory
noun
Physics Mathematics
The method of investigating solutions of equations representing physical systems, especially quantum systems, by relating them by means of perturbations to those of similar but simpler systems which can be solved directly.
Origin
1920s; earliest use found in Proceedings of the Royal Society of London.