Work

Generalized Wigner–Smith theory for perturbations at resonant exceptional and diabolic point degeneracies

Year: 2025

Type: article

Abstract: Resonant spectral degeneracies, including diabolic (DP) and exceptional (EP) points, exhibit unique sensitivity to external perturbations, enabling powerful control and engineering of wave phenomena. We present a residue-based perturbation theory that quantifies complex resonance splitting of DP and EP type spectral degeneracies using generalized Wigner-Smith operators. We validate our theory using both analytic Hamiltonian models and numerical electromagnetic simulations, demonstrating excellent agreement across a range of cases. Our approach accurately predicts degenerate resonance splitting using only scattering data, offering a powerful framework for sensitivity analysis, inverse design, and quantitative sensing.

Source: Optics Letters

DOI: 10.1364/ol.575813

Authors: Kaiyuan Wang, Niall Byrnes, Matthew R. Foreman

Institution: Nanyang Technological University

Language: English

Topic: Quantum Mechanics and Non-Hermitian Physics

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Ministry of Education - Singapore, Nanyang Technological University

Awards: G1088949837, G1231456110, G2030666203