Relativistic non-Fermi liquid fixed point in (2+1)-dimensional birefringent Dirac fermions interacting with electromagnetic fields

The system consisting of (2+1)-dimensional quasirelativistic birefringent Dirac fermions with Coulomb interactions and retarded current–current interactions is described by a quantum field theory similar to reduced quantum electrodynamics. We used the perturbative renormalization group method to study the low-energy behavior of the system and found that it flows to a fixed point of the non-Fermi liquid composed of relativistic pseudospin-1/2 Dirac fermions in the deep infrared limit. At the fixed point, the fermion Green function exhibits a finite anomalous dimension, and the residue of the quasiparticle pole vanishes in a power-law fashion. Our research provides new theoretical perspectives for understanding the origin of spin-1/2 fermions in the standard model.