Stochastic resonance and nonlinear response in double-quantum-well structures

Coherent motion of a wave packet in a double-quantum-well structure can be induced by irradiating it with a weak resonant laser field. The amplitude of this motion exhibits a ‘‘stochastic resonance’’ as a function of the relaxation rate in the double well and of the field amplitude. The maximum oscillation amplitude at each temperature does not depend on the field amplitude, demonstrating the failure of linear-response theory to describe the quantum stochastic resonance.