Effect of gauge boson mass on chiral symmetry breaking in QED$_{3}$
  In three-dimensional quantum electrodynamics (QED$_{3}$) with massive gauge boson, we investigate the Dyson-Schwinger equation for the fermion self-energy in the Landau gauge and find that chiral symmetry breaking (CSB) occurs when the gauge boson mass $\xi$ is smaller than a finite critical value $\xi_{cv}$ but is suppressed when $\xi > \xi_{cv}$. We further show that the critical value $\xi_{cv}$ does not qualitatively change after considering higher order corrections from the wave function renormalization and vertex function. Based on the relation between CSB and the gauge boson mass $\xi$, we give a field theoretical description of the competing antiferromagnetic and superconducting orders and, in particular, the coexistence of these two orders in high temperature superconductors. When the gauge boson mass $\xi$ is generated via instanton effect in a compact QED$_{3}$ of massless fermions, our result shows that CSB coexists with instanton effect in a wide region of $\xi$, which can be used to study the confinement-deconfinement phase transition. 
Guo-Zhu Liu and Geng Cheng