Spin diffusion and the anisotropic spin-1/2 Heisenberg chain
Abstract
Measurements of the spin-lattice relaxation rate 1/T_1 by nuclear magnetic resonance for the one-dimensional Heisenberg antiferromagnet Sr_2CuO_3 have provided evidence for a diffusion-like contribution at finite temperature and small wave-vector. By analyzing real-time data for the auto- and nearest-neighbor spin-spin correlation functions obtained by the density-matrix renormalization group I show that such a contribution indeed exists for temperatures T>J, where J is the coupling constant, but that it becomes exponentially suppressed for T << J. I present evidence that the frequency-dependence of 1/T_1 in the Heisenberg case is smoothly connected to that in the free fermion case where the exponential suppression of the diffusion-like contribution is easily understood.
Keywords
Cite
@article{arxiv.cond-mat/0604327,
title = {Spin diffusion and the anisotropic spin-1/2 Heisenberg chain},
author = {J. Sirker},
journal= {arXiv preprint arXiv:cond-mat/0604327},
year = {2007}
}
Comments
9 pages, 7 figures