Quantum response for chaotic resonances

Chaotic dynamics of conducting electrons in the presence of a high-frequenc y electromagnetic field and a constant homogeneous magnetic held is conside red. It is shown that quantum fluctuations become important in this case on a time scale shorter than mean free time. Nonperturbative approach for cal culation of a kinetic coefficient (conductivity) is developed. An analytica l expression for the kinetic coefficient as a function of the magnetic fiel d and a localization length is obtained. Dependence of the conductivity on the quantum localization length is studied.