Quantum coulomb particle on Minkowski plane

The problem of Coulomb nonrelativistic quantum particle on Minkowski plane is discussed. The cor- responding Schrödinger equation for eigenstates is obtained with the help of Beltrami-Laplas operator of pseudoeuclidean plane. The infinitely high poten- tial barriers are placed on isotropic lines. In contrast to the standard problem on euclidean plane, where there is only continuous energy spectrum, in the case of Minkowski plane there are unstable states which describe particle collapse onto isotropic line cone.