DISSOLVING OF CUSP FORMS: HIGHERâORDER FERMI'S GOLDEN RULES
DISSOLVING OF CUSP FORMS: HIGHERâORDER FERMI'S GOLDEN RULES
For a hyperbolic surface, embedded eigenvalues of the Laplace operator are unstable and tend to dissolve into scattering poles i.e. become resonances. A sufficient dissolving condition was identified by PhillipsâSarnak and is elegantly expressed in Fermi's golden rule. We prove formulas for higher approximations and obtain necessary and sufficient conditions âŚ