Coarsening in a driven Ising chain with conserved dynamics

We study the low-temperature coarsening of an Ising chain subject to spin-exchange dynamics and a small driving force. This dynamical system reduces to a domain diffusion process, in which entire domains undergo nearest-neighbor hopping, except for the shortest domains-dimers-which undergo long-range hopping. This system exhibits anomalous ordering dynamics due to the existence of two characteristic length scales: the average domain length L(t) approximately t(1/2) and the average dimer hopping distance l(t) approximately square root[L(t)] approximately t(1/4). As a consequence of these two scales, the density of short domains decays as t(-5/4), instead of the t(-3/2) decay that would arise from pure domain diffusion.