Relaxation dynamics of an elastic string in random media.
We investigate numerically the relaxation dynamics of an elastic string in two-dimensional random media by thermal fluctuations starting from a flat configuration. Measuring spatial fluctuations of its mean position, we find that the correlation length grows in time asymptotically as xi approximately (ln t)1/chi . This implies that the relaxation dynamics is driven by thermal activations over random energy barriers which scale as EB(l) approximately l;chi with a length scale l . Numerical data strongly suggest that the energy barrier exponent chi is identical to the energy fluctuation exponent chi=1/3 . We also find that there exists a long transient regime, where the correlation length follows a power-law dynamics as xi approximately t1/z with a nonuniversal dynamic exponent z . The origin of the transient scaling behavior is discussed in the context of the relaxation dynamics on finite ramified clusters of disorder.
Noh
Jae Dong
JD
Department of Physics, University of Seoul, Seoul 130-743, Korea.
Park
Hyunggyu
H