There are, of course, other, smaller corrections to the energies. You have found the bound state spectrum in more than one way and learned about the large degeneracy that exists for all states except the ground state. The energy levels of the hydrogen atom , taking account only of the Coulomb interaction between the electron and proton, are shown on the left.Perturbed energy levels , also including spin-orbit interaction and relativistic corrections, produce the so-called fine structure, as shown on the right. For , in the absence of fine structure, there are two states, two states, four states, four states, and six states, all of which are degenerate. Nevertheless, the states of definite total angular momentum are the energy eigenstates until we somehow break spherical symmetry. We have calculated the fine structure effects in Hydrogen. According to Eq. Hence, fine structure does not break the degeneracy of the and states of hydrogen, but does break the degeneracy of these states relative to the states. A correction from field theory, the Lamb Shift, causes states of different to shift apart slightly. Fine Structure c B. Zwiebach 2.1 Review of hydrogen atom The hydrogen atom Hamiltonian is by now familiar to you.