Stochastic description of the dynamics of a random-exchange Heisenberg chain

We study the diffusion process in a Heisenberg chain with correlated spatial disorder, with a power spectrum in the momentum space behaving as k − β , using a stochastic description. It establishes a direct connection between the fluctuation in the spin-wave density of states and the noise density o...

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Bibliographic Details
Published inPhysics letters. A Vol. 339; no. 1; pp. 33 - 38
Main Authors Vainstein, M.H., Morgado, R., Oliveira, F.A., de Moura, F.A.B.F., Coutinho-Filho, M.D.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 16.05.2005
Subjects
63.50.+x
62.30.+d
63.22.+m
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Summary:We study the diffusion process in a Heisenberg chain with correlated spatial disorder, with a power spectrum in the momentum space behaving as k − β , 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 β, 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.
ISSN:0375-9601
1873-2429
DOI:10.1016/j.physleta.2005.02.059