  The DC resistivity of charge density waves weakly-pinned by disorder is
controlled by diffusive, incoherent processes rather than slow momentum
relaxation. The corresponding incoherent conductivity can be computed in the
limit of zero disorder. We compute this transport coefficient in holographic
spatially modulated breaking translations spontaneously. As a by-product of our
analysis, we clarify how the boundary heat current is obtained from a conserved
bulk current, defined as a suitable generalization of the Iyer-Wald Noether
current of the appropriate Killing vector.
