Local Robustness of Bound States in the Continuum through Scattering-Matrix Eigenvector Continuation
This paper establishes a general topological framework for understanding the local robustness of bound states in the continuum (BICs) by characterizing them as isolated zeros of a parameter-to-coefficient mapping derived from scattering-matrix eigenvectors, thereby providing both a theoretical explanation for their phase singularities and a practical numerical criterion for their detection.