Perturbation Orders
The standard exposition of perturbation theory is given in terms of the order to which the perturbation is carried out: first-order perturbation theory or second-order perturbation theory, and whether the perturbed states are degenerate (that is, singular), in which case extra care must be taken, and the theory is slightly more difficult.
- This section needs to be expanded to include the standard textbook examples of each of the three expansions.
Read more about this topic: Perturbation Theory
Famous quotes containing the word orders:
“What is all wisdom save a collection of platitudes? Take fifty of our current proverbial sayings—they are so trite, so threadbare, that we can hardly bring our lips to utter them. None the less they embody the concentrated experience of the race and the man who orders his life according to their teaching cannot go far wrong.”
—Norman Douglas (1868–1952)