Unfolding of eigenvalue surfaces near a diabolic point due to a complex perturbation
Unfolding of eigenvalue surfaces near a diabolic point due to a complex perturbation
The paper presents a new theory of unfolding of eigenvalue surfaces of real symmetric and Hermitian matrices due to an arbitrary complex perturbation near a diabolic point.General asymptotic formulae describing deformations of a conical surface for different kinds of perturbing matrices are derived.As a physical application, singularities of the surfaces …