FINITE-TEMPERATURE EFFECTS IN THE NONINTEGRABLE SU(3) LIPKIN MODEL

In the present work we use nonrelativistic many body physics technique s to generalize the classical limit of quantum systems in such a way a s to incorporate statistical mixtures. Finite temperature effects are thus incorporated in a natural way. We give a detailed account of the thermodynamics of the SU(3) Lipkin model and then derive the classical thermal (chaotic) dynamics of the system. The most remarkable feature s of our analysis are twofold: firstly the appearance of a new degree of freedom essentially connected to thermal effects, i.e., for high en ough temperatures. Secondly we give a quantitative characterization of the temperature effects on the chaotic volume of the system. Thermal effects are shown to be responsible for novel nonlinear contributions to the dynamics and to consistently counterbalance the interaction par t of the dynamics. This is the case in the context both of thermodynam ics and of the thermal dynamics and we believe it to be true in genera l. (C) 1998 Academic Press.