Normal modes of the B=4 Skyrme soliton

The Skyrme model of nuclear physics requires quantization if it is to match observed nuclear properties. A simple technique is used to find the normal mode spectrum of the baryon number B = 4 Skyrme soliton. We find 16 vibrational modes and classify them under the cubic symmetry group O-h, of the static solution. The spectrum possesses a remarkable structure, with the lowest energy modes lying in those representations expected from an approximate correspondence between Skyrmions and Bogomolny-Prasad-Sommerfeld monopoles. The next mode up is the ''breather'', and above that are higher multipole breathing modes.