ABSTRACT
In order to fix ideas, let us consider a scattering object (quantum or classical) located in an isotropic, homogeneous, medium, the free space (vacuum included). Let a plane wave or radiation from a point source illuminate the scatterer. If the object is not too complex in nature, the scattering process is described by the boundary value problem [1–4] https://www.w3.org/1998/Math/MathML"> L ψ ( x → ) = s ( x → ) , x → ∈ R d , d = 1 , 2 , 3 , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429343537/18b98e44-b4d6-46f7-8d9d-b454d6765d91/content/equ_131-01.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> https://www.w3.org/1998/Math/MathML"> B ψ ( x → ) = f ( x → ) , x → ∈ Γ . https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429343537/18b98e44-b4d6-46f7-8d9d-b454d6765d91/content/equ_131-02.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
