Exact solutions for Dirac equation with one-dimensional symmetric Coulomb-type potentials
具有一维Coulomb型对称势Dirac方程的精确解

The energy levels of bound states for one dimensional Dirac equation are doubly degenerate provided that the scalar like potential is greater than the vector like potential. Arbitrary two wave functions with different eigenenergies and two wave functions with the same eigenenergy are orthogonal to each other. For a pure scalar potential the zero energy bound state does exist, and the fractional charge does exist.