One-electron spectral weight of doped Mott Insulators Gauge field theory   approach
  In this note we study the electron spectral weight of doped Mott insulators based on the 2D slave boson gauge field theory. The vertex correction with static gauge field is calculated in the second order perturbation theory. The vertex correction is found to be singular at low energy and requires non-perturbative treatments. 
H. C. Lee