a: = 2 a \"I!\" i!" a; m o u H H N I I 0 I I I fl: 2 (I 3 (I 4 Figure 4.3: Energy levels ofthe innine spherical well (Equation ) States with the same value of Name connected by dashed ling. Notice that die energy levels are (2! + ])-fold degenerate, since there are(2[' + 1) different values of m for each value of K (see Equation 429) This is the degeneracy to be expected for a spherically symmetric potential, since an dues not appear in the radial equation (which denermines due energy). Bur in some cases (most famously the hydrogen atom) [here is extra degeneracy, due to coincidences in the energy levels not attributable to spherical symmetry alane. The deeper reason for such \"accidental\" degeneracy is intriguing, as we shall see in Chapter