Does accidental degeneracy imply a symmetry group?

The relation between the appearance of accidental degeneracy in the energy levels of a given Hamiltonian and its symmetry group is probed. This is done by analyzing the very simple problem of an oscillator to which a particular spin-orbit and centrifugal force are added. The operators that connect all the states of given energy as well as their corresponding observables in the classical limit are found. The Poisson bracket relations between these observables leads to a Lie algebra U(3) × SU(2), but it does not translate into a Lie algebra for the commutators of the corresponding operators, as some matrix elements of commutators, corresponding to Poisson brackets that are zero, do not vanish. Thus while accidental degeneracy in the quantum problem may lead to a larger group in the classical limit, it is not always given by the dimensions of the irreducible representations of this group. © 1983.SCOPUS: ar.j