Hundred photon microwave ionization of Rydberg atoms in a static electric field

TL;DR

This paper investigates the microwave ionization of Rydberg atoms in a static electric field, revealing how photon number, dynamical localization, and internal chaos influence ionization processes.

Contribution

It provides analytical and numerical insights into high-photon ionization of nonhydrogenic atoms, highlighting the effects of dynamical localization and internal chaos on ionization thresholds.

Findings

Ionization is exponentially suppressed at low microwave fields due to dynamical localization.

Above the quantum delocalization border, ionization becomes diffusive.

Alkali atoms have a lower ionization border compared to hydrogen because of internal chaos.

Abstract

We present analytical and numerical results for the microwave excitation of nonhydrogenic atoms in a static electric field when up to 1000 photons are required to ionize an atom. For small microwave fields, dynamical localization in photon number leads to exponentially small ionization while above quantum delocalization border ionization goes in a diffusive way. For alkali atoms in a static field the ionization border is much lower than in hydrogen due to internal chaos.