Quantum control of stability of a discrete electron state coupled with a continuum by external oscillating fields

Abstract

Numerical and theoretical analysis of electron survival probability is presented for the system where a periodically driven discrete state is coupled with continuum states of the tight-binding model. The stability of the discrete state is examined by analyzing the survival probability in the weak-coupling case. Stable nondecaying states as well as usual unstable decaying states appear in the systems where the oscillating energy of the discrete state and the energy band of the continuum states overlap. Dynamical stable states caused by the energy oscillation are qualitatively explained by an approximate solution of a periodically driven two-level model. The decay is suppressed as a result of vanishing reduced coupling constant at the resonance.