QUANTUM TUNNELING IN THE DRIVEN LIPKIN N-BODY PROBLEM

Quantum tunneling is investigated in the quantum and semiclassical lim its using a periodically driven Lipkin N-body model. The time-dependen t driving changes the tunneling rate by orders of magnitude as compare d to the unperturbed system, leading to its enhancement in a somewhat similar way as found recently in the simple one-dimensional anharmonic -oscillator model for one particle. Oscillatory and coherent tunneling of the N-particle wave-function between two degenerate Hartree-Fock m inima is found when the initial wave-function is localized in one doub let of quasienergy states of different parity. The coherent suppressio n of tunneling is also found for specific parameters of the driving fo rce.