Effective field theory for ersatz Fermi liquids

We apply “hydrodynamic” effective field theory techniques to an ersatz Fermi liquid. Our effective theory, which captures the correlation functions of density operators at each angle on the Fermi surface, can only deviate from conventional Fermi liquid behavior if the effective theory is non-local. Neglecting non-local effects, the ersatz Fermi liquid’s effective action is the Legendre transform of the effective action for Fermi liquids, based on the coadjoint orbit method, up to irrelevant corrections.