Recent content by Evgn

In their article [Integrals in the theory of electron correlations, Annalen der Physik 7, 71] L.Onsager at el. write: By resolving the vector \vec{s} into its contravariant components in the oblique coordinate system formed by the vectors \vec{q} and \vec{Q} it is possible to reduce the region...

I'm studying a perturbation theory (behaviour of its series) and have found two articles which might be of particular interest. Unfortunately, all my three institutions do not have subscription to these journals (articles are too old). I'm kindly asking for your help. These are the articles I'm...

Sure, I use them to calculate matrix elements of perturbation. This part of calculation is indeed simple. What seems to be not simple is the calculation of the n-th order of perturbation series and not just 1st and 2nd like most textbooks do. 1st order correction is A |2\rangle, 2nd order - B...

Homework Statement Let's consider a harmonic oscillator with a harmonic perturbation: H = \frac{p^2}{2} + \frac{x^2}{2} + a \frac{x^2}{2}. Exact solution is known, but we want to derive it using perturbation theory. More specifically, suppose we want to obtain a series for the ground state...