The chiral phase transition of QED3 around the critical number of fermion flavors

At zero temperature and density, the nature of the chiral phase transition in QED₃ with N_f$N_f$ massless fermion flavors is investigated. To this end, in Landau gauge, we numerically solve the coupled Dyson–Schwinger equations for the fermion and boson propagator within the bare and simplified Ball–Chiu vertices separately. It is found that, in the bare vertex approximation, the system undergoes a high-order continuous phase transition from the Nambu–Goldstone phase into the Wigner phase when the number of fermion flavors N_f$N_f$ reaches the critical number N_f,c$N_{f,c}$, while the system exhibits a typical characteristic of second-order phase transition for the simplified Ball–Chiu vertex.