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math.AP2025
Spectra and pseudospectra of non-Hermitian Toeplitz operators: Eigenvector decay transitions in banded and dense matrices
Yannick de Bruijn, Bryn Davies, Sacha Dupuy +1
Using a generalised Floquet-Bloch theory, we present a mathematical method to construct eigenvectors for non-Hermitian Toeplitz operators. We extend the method to both banded Toepl…
math.AP2025
Complex Band Structure and localisation transition for tridiagonal non-Hermitian k-Toeplitz operators with defects
Yannick De Bruijn, Erik Orvehed Hiltunen
Using the Bloch-Floquet theory, we propose an innovative technique to obtain the eigenvectors of tridiagonal k-Toeplitz operators. This method offers a more extensive and quantitat…
math.AP2025
Complex Brillouin Zone for Localised Modes in Hermitian and Non-Hermitian Problems
Yannick De Bruijn, Erik Orvehed Hiltunen
We develop a mathematical and numerical framework for studying evanescent waves in subwavelength band gap materials. By establishing a link between the complex Brillouin zone and v…