ON THE CLASSICAL LIMITS IN THE SPIN-BOSON MODEL

The authors show that, while the classical equations of motion of Belobrov, Zaslavski and Tartakovski (1976) are rigorously obtained from the thermodynamic limit of the Heisenberg equations of motion of the many-atom version of the spin-boson model in suitable states, those of Milonni, Ackerhalt and Galbraith (1983) are derivable from a quantum Hamiltonian only if s)1/2, where s is the spin quantum number. Both equations are known to display chaotic behaviour for large coupling constants.