Date of Original Version
We calculate spin-autocorrelation functions (as time averages over chaotic trajectories) and their intensity spectra for clusters of two classical spins, interacting via a nonintegrable Hamiltonian. The long-time behaviour observed includes both power-law decay and persistent oscillatory components, resulting in an intensity spectrum with power-law singularities and discrete lines.
Niraj Srivastava, Charles Kaufman and Gerhard Müller. Regular and chaotic time evolution in spin clusters. J. Physique C8 (1988), 1601-1602.
Available at: http://dx.doi.org/10.1051/jphyscol:19888733