Path-integral approach for superintegrable potentials on spaces of nonconstant curvature: 1. Darboux spaces DI and DII

The Feynman path-integral technique is applied for superintegrable potentials on two-dimensional spaces of nonconstant curvature: these spaces are Darboux spaces Di and DII. On DI there are three and on DII four such potentials, respectively. It is possible to evaluate the path integral in the most of the separating coordinate systems, leading to expressions for the Green functions, the discrete and continuous wave functions, and the discrete energy spectra. In some cases, however, the discrete spectrum cannot be states explicitly, because it is either determined by a transcendental equation involving parabolic cylinder functions (Darboux space I), or by a higher order polynomial equation. It is possible to show how the limiting cases of flat space (constant zero curvature) and the two-dimensional hyperboloid (constant negative curvature) emerge