  We formulate a theory of dissipative hydrodynamics with spontaneously broken
translations, describing charge density waves in a clean isotropic electronic
crystal. We identify a novel linear transport coefficient, lattice pressure,
capturing the effects of background strain and thermal expansion in a crystal.
We argue that lattice pressure is a generic feature of systems with
spontaneously broken translations and must be accounted for while building and
interpreting holographic models. We also provide the first calculation of the
coefficients of thermal and chemical expansion in a holographic electronic
crystal.
