One-dimensional hydrogen in low-frequency radiation: Frequency-modulated hydrogen

We investigate the effect of intense, low-frequency fields on the structure of atomic hydrogen (prepared in the presence of an external dc electric field). The em field (of amplitude E0 and frequency) interacts with a low-lying (n in the range of 27) two-level system of one-dimensional hydrogen [transition frequency 0=(N+1) and transition dipole moment]. The field couples strongly to the permanent dipole moments of the two levels (d1 and d2), creating a large number of equally spaced sidebands (spacing equal to) that share among themselves. The distribution of the oscillator strength depends on the universal parameter (d2-d1)E0/. We determined the transition moment N of the Nth sideband for a variety of ladder and off-ladder systems. Our results indicate that at sufficiently high intensities that are comparable to the threshold of classical chaos of the many-level hydrogen-atom system, off-ladder sidebands become as strong as ladder sidebands, thus breaking the one dimensionality of the system.