https://doi.org/10.1140/epjp/i2012-12119-6
Regular Article
A simple iterative method to write the terms of any order of perturbation theory in quantum mechanics
1
Dipartimento di Fisica, Università di Pisa and INFN, Sezione di Pisa, Largo B. Pontecorvo 3, 56127, Pisa, Italy
2
INFN, Sezione di Pisa, Largo B. Pontecorvo 3, 56127, Pisa, Italy
* e-mail: bracci@df.unipi.it
Received:
6
August
2012
Revised:
11
September
2012
Accepted:
12
September
2012
Published online:
4
October
2012
The obvious fact that the eigenfunctions 
of the Hamiltonian 
are determined up to a phase factor 
can be used to exhibit a simple method to find the correction 
of order n to a non-degenerate energy level. Rules are given to write down all the terms which build up 
in terms of 
, 
, and series of matrix elements of the perturbation V .
© Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg, 2012
