Black Hole Entropy from Loop Quantum Gravity Speaker(s): Eugenio Bianchi
Abstract: There is strong theoretical evidence that black holes have a finite thermodynamic entropy equal to one quarter the area A of the horizon. Providing a microscopic derivation of the entropy of the horizon is a major task for a candidate theory of quantum gravity. Loop quantum gravity has been shown to provide a geometric explanation of the finiteness of the entropy and of the proportionality to the area of the horizon. The microstates are quantum geometries of the horizon. What has been missing until recently is the identification of the nearhorizon quantum dynamics and a derivation of the universal form of the BekensteinHawking entropy with its 1/4 prefactor. I report recent progress in this direction. In particular, I discuss the covariant spin foam dynamics and and show that the entropy of the quantum horizon reproduces the BekensteinHawking entropy S=A/4 with the proper onefourth coefficient for all values of the Immirzi parameter.
Date: 30/05/2012  2:00 pm
Series: Colloquium
