Effect of Interchain Coupling on Electron-Spin Resonance in Nearly One-Dimensional Systems

We show that the long-wavelength behavior in a nearly one-dimensional Heisenberg paramagnet is indeed described by an anisotropic diffusion tension, in contradiction to the assertion of Hennessy, McElwee, and Richards, and that their principle result, that "the rate for off-chain diffusion is proportional to $J^1{\left(\frac{J^1}{J}\right)}^{\frac{1}{3}}$" should be "the diffusion coefficient perpendicular to the chain axis is proportional to $J^1{\left(\frac{J^1}{J}\right)}^{\left(\frac{1}{3}\right)}$" where $J^1$ and $J$ are the exchange constants for the interaction of spins on adjacent chains and the same chain, respectively.