Quasi-Eigenstate Evolution in Open Chaotic Billiards

TL;DR

This paper experimentally investigates how quasi-eigenmodes evolve in open quantum billiards transitioning from regular to chaotic dynamics, revealing mode interactions and their relation to classical ray behavior.

Contribution

It introduces a method to trace and analyze mode evolution in deformed microcavities, linking quantum mode dynamics with classical chaos theory.

Findings

Observed avoided crossings between mode groups.

Quantified coupling strengths induced by ray chaos.

Linked mode dynamics to classical phase space behavior.

Abstract

We experimentally studied evolution of quasi-eigenmodes as classical dynamics undergoing a transition from being regular to chaotic in open quantum billiards. In a deformation-variable microcavity we traced all high-Q cavity modes in a wide range of frequency as the cavity deformation increased. By employing an internal parameter we were able to obtain a mode-dynamics diagram at a given deformation, showing avoided crossings between different mode groups, and could directly observe the coupling strengths induced by ray chaos among encountering modes. We also show that the observed mode-dynamics diagrams reflect the underlying classical ray dynamics in the phase space.