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1/ω-flux-noise and dynamical critical properties of two-dimensional XY-models

P. H. E. Tiesinga, T. J. Hagenaars, J. E. van Himbergen, Jorge V. José

cond-mat.supr-conarXiv:cond-mat/9611208

Abstract

We have numerically studied the dynamic correlation functions in thermodynamic equilibrium of two-dimensional O(2)-symmetry models with either bond (RSJ) or site (TDGL) dissipation as a function of temperature T. We find that above the critical temperature the frequency dependent flux noise SΦ(ω) 1+ (ω/Ω)2-α(T)/2, with 0.85≤ α(TDGL)(T)≤ 0.95 and 1.17 ≤ α(RSJ)(T) ≤ 1.27, while the dynamic critical exponents z(TDGL) 2.0 and z(RSJ) 0.9. Contrary to expectation the TDGL results are in closer agreement with the experiments in Josephson-junction arrays by Shaw et al., than those from the RSJ model. We find that these results are related to anomalous vortex diffusion through vortex clusters.

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