Free-fermion spectral structure enables strange nonchaotic attractor classification in Aubry-Andre-Harper quantum reservoirs
Abstract
An Aubry-André-Harper (AAH) quantum reservoir classifies strange nonchaotic attractors (SNAs) against chaos, substantially outperforming reservoirs built from dense random matrices on the full Fock space. Ablations and controlled interventions identify \emph{free-fermion one-body transition sparsity}, rather than proximity to a quantum phase transition, as the dominant factor under our controls, since H0 is quadratic in fermion operators and only N(N−1)2N−2=3584 of the 65,280 Fock-space transitions carry weight. Random on-site disorder, which preserves this quadratic structure, matches AAH accuracy, whereas full-Hilbert-space random matrices and eigenvector permutations, which break it, collapse to the random baseline. We characterize the resulting frequency-selective filtering with a Hamiltonian transition kernel, validate it to N=8 qubits, and reproduce it in a second dynamical system. We also use the reservoir as a training-free screen for strange-nonchaotic structure in Kepler RR Lyrae light curves.
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BibTeX
@misc{kumarasamy2026freefermion,
title = {{Free-fermion spectral structure enables strange nonchaotic attractor classification in Aubry-Andre-Harper quantum reservoirs}},
author = {Suresh Kumarasamy and Dianavinnarasi Joseph and Manish Dev Shrimali and Awadhesh Prasad},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.26825},
eprint = {2609.26825},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.26825},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Free-fermion spectral structure enables strange nonchaotic attractor classification in Aubry-Andre-Harper quantum reservoirs
AU - Suresh Kumarasamy
AU - Dianavinnarasi Joseph
AU - Manish Dev Shrimali
AU - Awadhesh Prasad
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.26825
UR - https://arxiv.org/abs/2609.26825
AB - An Aubry-André-Harper (AAH) quantum reservoir classifies strange nonchaotic attractors (SNAs) against chaos, substantially outperforming reservoirs built from dense random matrices on the full Fock space. Ablations and controlled interventions identify \emph{free-fermion one-body transition sparsity}, rather than proximity to a quantum phase transition, as the dominant factor under our controls, since H_0 is quadratic in fermion operators and only N(N−1)2^N−2=3584 of the 65,280 Fock-space transitions carry weight. Random on-site disorder, which preserves this quadratic structure, matches AAH accuracy, whereas full-Hilbert-space random matrices and eigenvector permutations, which break it, collapse to the random baseline. We characterize the resulting frequency-selective filtering with a Hamiltonian transition kernel, validate it to N=8 qubits, and reproduce it in a second dynamical system. We also use the reservoir as a training-free screen for strange-nonchaotic structure in Kepler RR Lyrae light curves.
ER -