TUNNELING RATE FLUCTUATIONS INDUCED BY NONLINEAR RESONANCES - A QUANTITATIVE TREATMENT BASED ON SEMICLASSICAL ARGUMENTS

We investigate the tunneling process between two symmetric stable isla nds of a forced pendulum Hamiltonian in the weak chaos regime. We show that when the tunneling doublet is quantized over a classical nonline ar resonance the tunneling rate strongly deviates from the semiclassic al prediction. This mechanism is responsible for the irregular depende nce of the tunneling rate on the system parameters. The weak-chaos con dition allows us to make a theoretical prediction that agrees very wel l with the numerical results. This opens up a possible avenue to a gen eral theory on the dependence of quantum tunneling on classical chaos. [S1063-651X(98)06511-8].