Note on Brane-antibrane Description of Non-extremal Black Holes
  Recently a number of authors have used a system of branes and antibranes at finite temperature for microscopic modeling of non-extremal black holes in string theory. The entropy of the system is derived from the simplified assumption of decoupled gas of open strings on the stacks of branes and antibranes and extremizing the total entropy with respect to the number of branes (or antibranes). The resulting entropy differs from the supergravity entropy by a deficit factor. We give an intuitive explanation for the deficit factor. We treat the whole system as two stacks of branes and antibranes with a single copy of Yang-Mills gas common to both the stacks. This gives the answer in agreement with the supergravity. 
Sanjay Siwach