Narrow near-threshold resonances of the hydrogen atom in strong magnetic fields

Abstract

Continuum states and bound states of the hydrogen atom in a strong magnetic field are studied for field strengths somewhat smaller than $B_0=2.35\mathrm{}\times {10}^9$ G, and for azimuthal quantum numbers up to $\left|m\right|=2\mathrm{}$. At field strengths for which the third Landau excited state in a given $m^{\pi }$ subspace with positive $z$ parity $\pi$ lies close to the ionization threshold, the width of this state is orders of magnitude smaller than might be expected from the widths of the two lower-lying Landau excited states in the respective $m^{+}$ subspace.