  The relativistic hydrogen atom in an Euclidean space-time of arbitrary number
of space dimensions ($D$) plus one time dimension is revisited. In particular,
numerical solutions of the radial Dirac equation for a generalized Coulombian
potential proportional to $1/r^{(D-2)}$ are investigated. It is argued that one
could not find any physical solution for $D\geq 4$.

Quantum Physics