The anisotropic oscillator on curved spaces: A new exactly solvable model

We present a new exactly solvable (classical and quantum) model that can be interpreted as the generalization to the two-dimensional sphere and to the hyperbolic space of the two-dimensional anisotropic oscillator with any pair of frequencies cox and coy. The new curved Hamiltonian H-K depends on the curvature kappa of the underlying space as a deformation/contraction parameter, and the Liouville integrability of H-K relies on its separability in terms of geodesic parallel coordinates, which generalize the Cartesian coordinates of the plane. Moreover, the system is shown to be superintegrable for commensurate frequencies omega(x) : omega(y) thus mimicking the behaviour of the flat Euclidean case, which is always recovered in the is kappa -> 0 limit. The additional constant of motion in the commensurate case is, as expected, of higher-order in the momenta and can be explicitly deduced by performing the classical factorization of the Hamiltonian. The known 1 : 1 and 2 : 1 anisotropic curved oscillators are recovered as particular cases of H-K, meanwhile all the remaining omega(x) : omega(y) curved oscillators define new superintegrable systems. Furthermore, the quantum Hamiltonian H-K is fully constructed and studied by following a quantum factorization approach. In the case of commensurate frequencies, the Hamiltonian H-K turns out to be quantum superintegrable and leads to a new exactly solvable quantum model. Its corresponding spectrum, that exhibits a maximal degeneracy, is explicitly given as an analytical deformation of the Euclidean eigenvalues in terms of both the curvature kappa and the Planck constant h. In fact, such spectrum is obtained as a composition of two one-dimensional (either trigonometric or hyperbolic) Posch-Teller set of eigenvalues. (C) 2016 Elsevier Inc. All rights reserved.