A neutron star is a highly dense remnant formed from a supernova explosion at the end of a star's life cycle. It is composed primarily of neutrons, with few protons present forming crystaline lattice, which have significant effects on the star's behavior. Both neutrons and protons are fermions, and at the extreme densities found in neutron stars, they become highly degenerate. Due to attractive interactions, certain layers of the neutron star transition into a superfluid state, which can be indirectly observed through astronomical observations.

In this presentation, I will explain how energy is dissipated when an obstacle (a proton impurity) moves through the neutron superfluid. I will explore the possible dissipation channels and their potential astrophysical implications. The results are derived from an extension of density functional theory for superfluid systems. The mechanisms studied are universal and may also apply to other fermionic superfluids, such as ultracold gases and liquid helium.