Ground state, factors determining spin-configuration

Prefactor A (i.e., the Van Vleck determinant) in Eq. (448) relates to fluctuations around the classical path. It should be noted that the utilization of the singledomain approximation (445) partly ignores a contribution on the side of unordered spin configurations to wave functions of the ground states that is, any term similar to To in expression (442), the decoherence factor, is omitted. Thus, the spin-spin interaction results in the coherent behavior of a magnetic one-domain particle. 

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