A realistic example of chaotic tunneling: The hydrogen atom inparallel static electric and magnetic fields
Résumé
Statistics of tunneling rates in the presence of chaotic classicaldynamics is discussed on a realistic example: a hydrogen atomplaced in parallel uniform static electric and magnetic fields, wheretunneling is followed by ionization along the fields direction.Depending on the magnetic quantum number, one may observe eithera standard Porter-Thomas distribution of tunneling rates or,for strong scarring by a periodic orbit parallel to the externalfields, strong deviations from it. For the latter case, a simple model based onrandom matrix theory gives the correct distribution.