Abstract
The spin-lattice relaxation rate 1/ and the spin-echo decay rate 1/ for the spin-1/2 antiferromagnetic Heisenberg chain are calculated using quantum Monte Carlo and maximum-entropy analytic continuation. The results are compared with recent analytical calculations by Sachdev. If the nuclear hyperfine form factor is strongly peaked around q=π, the predicted low-temperature behavior [1/∼(1/T), 1/∼(1/T)/√T] extends up to temperatures as high as T/J≊0.5. If has significant weight for q≊0 there are large contributions from diffusive long-wavelength processes not taken into account in the theory, and very low temperatures are needed in order to observe the asymptotic T→0 forms.
- Received 13 June 1995
DOI:https://doi.org/10.1103/PhysRevB.52.R9831
©1995 American Physical Society