Stochastic description of the dynamics of the random-exchange Heisenberg chain
arXiv:cond-mat/0308542 · doi:10.1016/j.physleta.2005.02.059
Abstract
We study the diffusion process in a Heisenberg chain with correlated spatial disorder, with a power spectrum in the momentum space behaving as , using a stochastic description. It establishes a direct connection between the fluctuation in the spin-wave density of states and the noise density of states. For continuous ranges of the exponent , we find superdiffusive and ballistic spin-wave motions. Both diffusion exponents predicted by the stochastic procedure agree with the ones calculated using the Hamiltonian dynamics.
6 pages, 4 figures