Self-gravitating nonlinear Dirac fields

We consider the self-gravitating Dirac field with a scalar fermion self-interaction term. For strong enough attractive fermion self-interaction, the maximum Arnowitt–Deser–Misner mass of soliton solutions consisting of two fermions can exceed the limit of noninteracting Dirac stars classically, and the “particle-like” solutions of the system can exhibit multiplicity, multiple valid solutions for a single set of parameters, that is inherent in the nonlinear Dirac field. We also find the mass-scale separation in our system similar to that discussed in the Einstein–Dirac–Higgs system. Interestingly, the system admits parity-violated solutions. The broken parity symmetry can be restored by increasing the central redshift of the solution.