Superfluid Neutron Stars

Neutrons stars are believed to contain in their interior superfluid neutrons and superconducting protons. This is suggested by nuclear physics calculations and by the very long relaxation time scales after ‘glitches’ (sudden increases of the neutron star angular velocity). Over the last years, we have been developing a formalism that can describe the relativistic hydrodynamics of mixtures of superfluid or superconductors and possibly ordinary fluids . The hydrodynamics of several species labelled by the index X, with respective particle currents n ρ X and respective electric charge per particle e , can be described by the Lagrangian