An algebraic approach to solving degenerate perturbation theory is exhibited. This approach is used to solve the canonical Berry phase problem in the Born-Oppenheimer approximation, as well as the analogous classical problem. The show variables need not commute. Non-abelian phases and field theory anomalies are treated as examples. A non-adiabatic extension is suggested.
ASJC Scopus subject areas
- Nuclear and High Energy Physics