A method of calculating eigenvalues in the spectral gaps of self-adjoint elliptic partial
differential equations on waveguides is presented. It is based on approximating the problem …

An algorithm is presented for calculating eigenvalues lying in the spectral gaps of the
essential spectrum of Schrödinger operators. The method is applicable to the scalar and …

In this paper, we introduce a new convergence mode to deal with the generalized spectrum
approximation of two bounded operators. This new technique is obtained by extending the …

Spectral inclusion and spectral pollution results are proved for sequences of linear operators
of the form T 0+ iγs n on a Hilbert space, where sn is strongly convergent to the identity …

We consider Schrödinger operators of the form H_R=-\, d^ 2/\, dx^ 2+ q+ i γ χ _ 0, R HR=-d
2/dx 2+ q+ i γ χ 0, R for large R> 0 R> 0, where q ∈ L^ 1 (0, ∞) q∈ L 1 (0,∞) and γ> 0 γ> 0 …

In this thesis, we study the spectrum of Schrödinger operators with complex potentials and
Dirichlet Laplace operators on domains with rough boundaries. The focus is on spectral …

Spectral problems of band-gap structure appear in various applications such as elasticity
theory, electromagnetic waves, and photonic crystals. In the numerical approximation of …

In this paper, we introduce a new convergence mode to deal with the generalized spectrum
approximation of two bounded operators. This new technique is obtained by extending the …

We develop computational tools for exploring eigenvector localization for a class of
selfadjoint, elliptic eigenvalue problems regardless of the cause for localization. The user …