LOW-ENERGY WAVE-PACKET TUNNELING FROM A PARABOLIC POTENTIAL WELL THROUGH A HIGH-POTENTIAL BARRIER

The problem of wave packet tunneling in a potential V(x) = 1/2m omega( 2)(x(2) - delta x(nu)) with nu > 2 is considered in the case when the barrier height is much greater than tiw and the difference between the average energy of the packet and the oscillator ground state energy < 1/2(h)over bar omega> is sufficiently small. The universal Poisson dis tribution of the partial tunneling rates from the oscillator energy le vels is found. The explicit expressions for the tunneling rates of dif ferent types of packets (coherent, squeezed, even/odd, thermal, etc.) are given in terms of the exponential and modified Bessel functions. T he tunneling rates turn out to be very sensitive to the energy distrib utions in the packets, and they may exceed significantly the tunneling rate from the energy state with the same average number of quanta.