Exact solutions to the Dirac equation for a Coulomb potential in $D+1$   dimensions
  The Dirac equation is generalized to $D+1$ space-time.The conserved angular momentum operators and their quantum numbers are discussed. The eigenfunctions of the total angular momenta are calculated for both odd $D$ and even $D$ cases. The radial equations for a spherically symmetric system are derived. The exact solutions for the system with a Coulomb potential are obtained analytically. The energy levels and the corresponding fine structure are also presented. 
Xiao-Yan Gu, Zhong-Qi Ma, and Shi-Hai Dong