The coarsening dynamics of the Cahn-Hilliard equation with order-parameter
dependent mobility, λ(ϕ)∝(1−ϕ2)α, is addressed at
zero temperature in the Lifshitz-Slyozov limit where the minority phase
occupies a vanishingly small volume fraction. Despite the absence of bulk
diffusion for α>0, the mean domain size is found to grow as ∝t1/(3+α), due to subdiffusive transport of the order parameter
through the majority phase. The domain-size distribution is determined
explicitly for the physically relevant case α=1.Comment: 4 pages, Revtex, no figure