Regarding confinement and dynamical chiral symmetry breaking in QED3

Understand

We establish that QED3 can possess a critical number of flavours, N_f^c, associated with dynamical chiral symmetry breaking if, and only if, the fermion wave function renormalisation and photon vacuum polarisation are homogeneous functions at infrared momenta when the fermion mass function vanishes.

• The Ward identity entails that the fermion-photon vertex possesses the same property and ensures a simple relationship between the homogeneity degrees of each of these functions.
• Simple models for the photon vacuum polarisation and fermion-photon vertex are used to illustrate these observations.
• The existence and value of N_f^c are contingent upon the precise form of the vertex but any discussion of gauge dependence is moot.