Pion fluctuations around a moving and rotating Skyrmion

Fluctuating pion fields around a moving and rotating Skyrmion are quantized by Dirac's method. Both the rotational and translational collective motion of the Skyrmion are described by collective coordinates and then all six zero-frequency modes of the pion field are eliminated. The method allows us to treat fluctuations around a soliton consistently with its collective rotational and translational motion. Pion-baryon linear couplings are studied and the $\Delta \to N\pi$ decay rate is calculated.