Phase Transition of Spherical Phonon System

抄録

A critical behaviour of “spherical phonon system” is studied, which is a tentative model useful for the consideration of the ferroelectric phase transitions in anharmonic lattices. The mechanism of the phase transition in this system can be interpreted as a Bose-Einstein condensation of spherical phonons based upon a freeze of chemical potential. The results obtained by the classical and the quantum-mechanical treatments are compared with that of previous theories given by Lines, Tokunaga and Matsubara, Larkin and Vaks, et al.