Bloch particle in the presence of dc and ac fields:: Statistics of the Wigner delay time

The paper studies quantum states of a Bloch particle in the presence of external ac and de fields. Provided the period of the ac field and the Bloch period are commensurate, an effective scattering matrix is introduced, the complex poles of which are the system quasienergy spectrum. The statistics of the resonance width and the Wigner delay time shows a close relation of the problem to random matrix theory of chaotic scattering.[S0031 -9007(99)08408-2].