Scattering theory for the Schrödinger equation with repulsive potential
Résumé
We consider the scattering theory for the Schrödinger equation with $-\\Delta -|x|^{\\alpha}$ as a reference Hamiltonian, for $0< \\alpha \\leq 2$, in any space dimension. We prove that when this Hamiltonian is perturbed by a potential, the usual short range/long range condition is weakened: the limiting decay for the potential depends on the value of $\\alpha$, and is related to the growth of classical trajectories in the unperturbed case. The existence of wave operators and their asymptotic completeness are established thanks to Mourre estimates relying on new conjugate operators. We construct the asymptotic velocity and describe its spectrum. Some results are generalized to the case where $-|x|^{\\alpha}$ is replaced by a general second order polynomial.