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Spin diffusion and the anisotropic spin-1/2 Heisenberg chain

J. Sirker
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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.

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J. Sirker. 2006-04-12. Spin diffusion and the anisotropic spin-1/2 Heisenberg chain. https://doi.org/10.1103/physrevb.73.224424

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