| Previous research suggested that the critical mass of constant-density neutron stars will be greater than eight solar masses when the majority of their neutrons condense into bosons that form a Bose-Einstein condensate, provided the bosons interact with each other and have scattering lengths on the order of a picometer. That analysis was able to use Newtonian theory for the condensate with scattering lengths on this order, but general relativity provides a more fundamental analysis. This thesis determines the equilibrium states of a static, spherically-symmetric variable-density mixture of a degenerate gas of noninteracting neutrons and a Bose-Einstein condensate using general relativity. It uses a Klein-Gordan Lagrangian density with a Gross-Pitaevskii term for the condensate and an effective field approximation for the neutrons. The resulting calculations show that large boson scattering lengths may prevent neutron stars from collapsing into stellar black holes. provided that the nuclear pairing gap is also large. |
