Low-Density Neutron Matter and the Unitary Limit

We review the properties of neutron matter in low-density regime. In particular, we revise its ground state energy and superfluid pairing gap analyze their evolution from weak to strong coupling The calculations are performed, respectively, within Brueckner–Hartree–Fock (BHF) approach nuclear Bardeen–Cooper–Schrieffer (BCS) theory using chiral nucleon-nucleon interaction Entem Machleidt at N 3 LO Argonne V18 phenomenological potential. Results for also shown a simple Gaussian potential with strength range adjusted reproduce 1 S 0 neutron-neutron scattering length effective range. Our results compared those quantum Monte Carlo (QMC) cold atoms. Tan contact parameter is calculated, finding reasonable agreement experimental data ultra-cold atoms only very low densities. find that exhibits behavior close Fermi gas unitary limit, although, this limit actually never reached. (energy, mass, quasiparticle residue) spin-down impurity immersed free spin-up neutrons already studied by author recent work where it was these an attractive polaron limit.