Ericson fluctuations in the chaotic ionization of the hydrogen atom in crossed magnetic and electric fields

We report exact quantum calculations for the hydrogen atom in crossed magnetic and electric fields. Employing the complex-coordinate-rotation method we are able to extend the calculations of eigenstates far into the continuum region. Calculated photoionization cross sections are found to exhibit strong Ericson fluctuations, a characteristic feature of chaotic scattering. This interpretation is supported by classical trajectory calculations which reveal a fractal dependence of the classical ionization time on the initial conditions