Quantum Stabilization by Coherent Population of Scarred Eigenstates: Quantum Suppression of Transport Classically Initiated by Separatrix Band Entry

TL;DR

This paper demonstrates that selective population of scarred eigenstates in a quantum system can suppress classical transport mechanisms, leading to increased stability in a hydrogen atom under pulsed microwave fields.

Contribution

It reveals the quantum stabilization mechanism via scarred eigenstates and analyzes the role of classical resonance zones using Floquet theory and Husimi functions.

Findings

Quantum stabilization linked to scarred eigenstates.

Frequency range of stabilization influenced by classical resonance zones.

Quantum resonances can destabilize certain Floquet states.

Abstract

Comparisons of experimental data with numerical predictions of a classical model indicate that an excited hydrogen atom in a pulsed microwave electric field exhibits a nonclassical increase of stability over a relatively wide range of frequencies. I show here that this is due to selective population of long-lived "scarred" states that are associated with the chaotic separatrix band surrounding the principal classical resonance zone in phase space. A quantum explanation is given in terms of adiabatic evolution of Floquet states and the destabilizing effect of two-level quantum resonances is investigated. The role of neighbouring classical resonance zones in defining the frequency range of stabilization is revealed both by quasienergy curves and by Husimi functions for the instantaneous quantum states.