Dynamical localization of chaotic eigenstates in the mixed-type systems: spectral statistics in a billiard system after separation of regular and chaotic eigenstates

TL;DR

This study investigates high-energy eigenstates in a mixed-type billiard system, revealing that chaotic eigenstates are dynamically localized and that spectral statistics follow Poisson and Brody distributions for regular and chaotic states, respectively.

Contribution

It introduces a reliable overlap criterion to distinguish regular and chaotic eigenstates at very high energies, demonstrating their localization properties and spectral statistics with high precision.

Findings

Chaotic eigenstates are dynamically localized, not spread over entire chaotic phase space.

Regular levels follow Poisson statistics, chaotic levels follow Brody statistics.

No significant dynamical tunneling effects observed at high energies.

Abstract

We study the quantum mechanics of a billiard (Robnik 1983) in the regime of mixed-type classical phase space (the shape parameter \lambda=0.15) at very high-lying eigenstates, starting at about 1.000.000th eigenstate and including the consecutive 587654 eigenstates. By calculating the normalized Poincar\'e Husimi functions of the eigenstates and comparing them with the classical phase space structure, we introduce the overlap criterion which enables us to separate with great accuracy and reliability the regular and chaotic eigenstates, and the corresponding energies. The chaotic eigenstates appear all to be dynamically localized, meaning that they do not occupy unformly the entire available chaotic classical phase space component, but are localized on a proper subset. We find with unprecedented precision and statistical significance that the level spacing distribution of the regular levels obeys the Poisson statistics, and the chaotic ones obey the Brody statistics, as anticipated in a recent paper by Batisti\'c and Robnik (2010), where the entire spectrum was found to obey the BRB statistics. There are no effects of dynamical tunneling in this regime, due to the high energies, as they decay exponentially with the inverse effective Planck constant which is proportional to the square root of the energy.