Vacuum polarization of fermions near the throat of a global monopole wormhole

Abstract We investigate the fermion system excited by a free Dirac spinor field near the throat of a global monopole wormhole, characterized by the equation-of-state parameter $$\xi $$ ξ of the exotic fluid supporting the wormhole and the symmetry-breaking scale $$\eta $$ η of the monopole. From the perspective of the spacetime metric alone, there have no significant distinction for different values of $$\xi $$ ξ and $$\eta $$ η . However, when the spinor field is introduced as a probe and macroscopic physical quantities, such as fermion condensation, energy density, radial pressure, and angular stress, are calculated, we find that these quantities are able to uncover distinct physical behaviors corresponding to different combinations of $$\xi $$ ξ and $$\eta $$ η . Meanwhile, we find that the fermion condensation is closely related to the strong energy condition and undergoes a notable phase transition as $$\eta $$ η increases. Furthermore, the free energy density is analyzed to investigate the stability of the fermion system under varying parameter combinations of $$\xi $$ ξ and $$\eta $$ η . Besides, both scenarios of normal fermions and exotic fermions are considered in this analysis, highlighting the contrasting physical properties between these two cases.