Exactly solvable deformations of the oscillator and Coulomb systems and   their generalization
  We present two maximally superintegrable Hamiltonian systems ${\cal H}_\lambda$ and ${\cal H}_\eta$ that are defined, respectively, on an $N$-dimensional spherically symmetric generalization of the Darboux surface of type III and on an $N$-dimensional Taub-NUT space. Afterwards, we show that the quantization of ${\cal H}_\lambda$ and ${\cal H}_\eta$ leads, respectively, to exactly solvable deformations (with parameters $\lambda$ and $\eta$) of the two basic quantum mechanical systems: the harmonic oscillator and the Coulomb problem. In both cases the quantization is performed in such a way that the maximal superintegrability of the classical Hamiltonian is fully preserved. In particular, we prove that this strong condition is fulfilled by applying the so-called conformal Laplace-Beltrami quantization prescription, where the conformal Laplacian operator contains the usual Laplace-Beltrami operator on the underlying manifold plus a term proportional to its scalar curvature (which in both cases has non-constant value). In this way, the eigenvalue problems for the quantum counterparts of ${\cal H}_\lambda$ and ${\cal H}_\eta$ can be rigorously solved, and it is found that their discrete spectrum is just a smooth deformation (in terms of the parameters $\lambda$ and $\eta$) of the oscillator and Coulomb spectrum, respectively. Moreover, it turns out that the maximal degeneracy of both systems is preserved under deformation. Finally, new further multiparametric generalizations of both systems that preserve their superintegrability are envisaged. 
Angel Ballesteros, Alberto Enciso, Francisco J. Herranz, Orlando   Ragnisco and Danilo Riglioni
quant-ph math-ph math.MP nlin.SI