Some Unique Constants Associated with Extremal Black Holes
  In recent papers we had developed a unified picture of black hole entropy and curvature which was shown to lead to Hawking radiation. It was shown that for any black hole mass, holography implies a phase space of just one quantum associated with the interior of the black hole. Here we study extremal rotating and charged black holes and obtain unique values for ratios of angular momentum to entropy, charge to entropy, etc. It turns out that these ratios can be expressed in terms of fundamental constants in nature, having analogies with other physical systems, like in condensed matter physics. 
C. Sivaram (1) and Kenath Arun (2) ((1) Indian Institute of   Astrophysics, Bangalore, (2) Christ Junior College, Bangalore)
physics.gen-ph