Pairing Gaps in low-density neutron matter and in cold atoms

Hsuan‐Hao Fan

Joseph Carlson

Heng Fan, E. Krotscheck

Armen Sedrakian, J. W. Clark, E. Krotscheck

Alexandros Gezerlis, Joseph Carlson

Experiments with cold Fermi atoms can be tuned to probe strongly-interacting fluids that are very similar to the low-density neutron matter found in the crusts of neutron stars. In contrast to traditional superfluids and superconductors, matter in this regime is very strongly paired, with gaps of the order of the Fermi energy. We compute the $T=0$ equation of state and pairing gap for cold atoms and low-density neutron matter as a function of the Fermi momentum times the scattering length. Results of quantum Monte Carlo calculations show that the equations of state are very similar. The neutron matter pairing gap at low densities is found to be very large but, except at the smallest densities, significantly suppressed relative to cold atoms because of the finite effective range in the neutron-neutron interaction.

Joseph Carlson, Alexandros Gezerlis, Sanjay K. Reddy +3 more

Cold Atom experiments provide a direct experimental test of the properties of neutron matter at extremely low densities, as is expected to be found in the crusts of neutron stars. These systems are very unusual in that the pairing gap is of the order of the Fermi energy, rather than the very small fraction typical for superfluids or superconductors. We compare the equation of state and the pairing gaps in these systems.