PARTIAL DYNAMICAL SYMMETRY AND THE SUPPRESSION OF CHAOS

Partial dynamical symmetry is a situation in which the Hamiltonian doe s not have a certain symmetry yet a subset of its eigenstates does. It is shown that partial dynamical symmetry may cause suppression of cha os even in cases where the fraction of states which has the symmetry v anishes in the classical limit. The average entropy associated with th e symmetry is a sensitive quantum measure of the partial symmetry and its effect on the chaotic dynamics.