Optimal cylindrical and spherical Bessel transforms satisfying bound state boundary conditions Original Research Article

Optimal discrete transforms based upon the radial Laplacian eigenfunctions in cyclindrical and spherical coordinates are presented, featuring the following properties: (1) bound state boundary conditions are enforced; (2) in the case of cylindrical or spherical symmetry, the relevant discrete Bessel transform (DBT) is analogous to the discrete Fourier transform in Cartesian coordinates; (3) the underlying quadrature algorithms achieve a Gaussian-like accuracy; (4) orthogonality of the transform can be ensured even in the absence of symmetry. Efficient multidimensional pseudospectral schemes are thus enabled in either direct or nondirect product representations. The illustrative program computes the various DBTs and applies them to the eigenvalue calculation for the two- and three-dimensional harmonic oscillator.