arXiv subjects

Jan Robert Schmidt

Publications and source records attributed to Jan Robert Schmidt.

4 recordsLinked to original sources

arXiv2025

Semiclassical Limit of Resonance States in Chaotic Scattering

Resonance states in quantum chaotic scattering systems have a multifractal structure that depends on their decay rate. We show how classical dynamics describes this structure for all decay rates in the semiclassical limit. This result for chaotic scattering systems corresponds to the well-established quantum ergodicity for closed chaotic systems. Specifically, we generalize Ulam's matrix approximation of the Perron-Frobenius operator, giving rise to conditionally invariant measures of various decay rates. There are many matrix approximations leading to the same decay rate and we conjecture a criterion for selecting the one relevant for resonance states. Numerically, we demonstrate that resonance states in the semiclassical limit converge to the selected measure. Example systems are a dielectric cavity, the three-disk scattering system, and open quantum maps.

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arXiv2023

Resonance states of the three-disk scattering system

For the paradigmatic three-disk scattering system, we confirm a recent conjecture for open chaotic systems, which claims that resonance states are composed of two factors. In particular, we demonstrate that one factor is given by universal exponentially distributed intensity fluctuations. The other factor, supposed to be a classical density depending on the lifetime of the resonance state, is found to be very well described by a classical construction. Furthermore, ray-segment scars, recently observed in dielectric cavities, dominate every resonance state at small wavelengths also in the three-disk scattering system. We introduce a new numerical method for computing resonances, which allows for going much further into the semiclassical limit. As a consequence we are able to confirm the fractal Weyl law over a correspondingly large range.

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arXiv2023

Classical Drift in the Arnold Web Induces Quantum Delocalization Transition

We demonstrate that quantum dynamical localization in the Arnold web of higher-dimensional Hamiltonian systems is destroyed by an intrinsic classical drift. Thus quantum wave packets and eigenstates may explore more of the intricate Arnold web than previously expected. Such a drift typically occurs, as resonance channels widen toward a large chaotic region or toward a junction with other resonance channels. If this drift is strong enough, we find that dynamical localization is destroyed. We establish that this drift-induced delocalization transition is universal and is described by a single transition parameter. Numerical verification is given using a time-periodically kicked Hamiltonian with a four-dimensional phase space.

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arXiv2022

Resonance states at Casati wave numbers for the 3-disk billiard

Resonance states of the 3-disk scattering system are presented for the first Casati wave number $k \approx 912$ and the second Casati wave number $k \approx 91242$. They show multifractal structure in phase space, similar to the pioneering work by Casati et al. [Physica D 131, 311 (1999)] for an open chaotic quantum map. In position space we observe scarring along segments of rays, related to multifractality and universal fluctuations, as recently found for dielectric cavities. To the best of our knowledge this resonance state at the second Casati wave number has a much larger wave number than published resonance states for the 3-disk scattering system or any other open or closed chaotic billiard.

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