Non-resonant driving of an H atom with broken time-reversal symmetry

The dynamics of atomic hydrogen placed in a static electric field and illum inated by elliptically polarized microwaves is studied in the range of smal l field amplitudes where perturbation calculations are applicable. For a ge neral configuration of the fields any generalized time-reversal symmetry is broken and, as the classical dynamics is chaotic, the level statistics obe ys the random matrices prediction of a Gaussian unitary ensemble.