Logarithmic Conformal Field Theory Through Nilpotent Conformal   Dimensions
  We study logarithmic conformal field theories (LCFTs) through the introduction of nilpotent conformal weights. Using this device, we derive the properties of LCFT's such as the transformation laws, singular vectors and the structure of correlation functions. We discuss the emergence of an extra energy momentum tensor, which is the logarithmic partner of the energy momentum tensor. 
S. Moghimi-Araghi, S. Rouhani and M. Saadat