The low energy dynamics of the neutron star crust is relevant to understanding diverse neutron star phenomena such as superbursts, giant flares, thermal relaxation and pulsar glitches. In the crust a lattice of ions coexists with a superfluid and the coupling between these systems is strong. This coupling has been ignored in all previous studies of the neutron star crust.  Vincenzo, Sanjay, and Rishi have formulated an effective field theory to describe this coupling and its implications for oscillations and entrainment in the neutron star crust. The manuscript is available for comment.   

The figure shows how neutron-proton interactions induce a mixing between two longitudinal modes of the lattice and the superfluid in the crust.