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Journal Article

#### Isolated Horizons and Black Hole Entropy in Loop Quantum Gravity

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##### Fulltext (public)

1112.0291

(Preprint), 2MB

sigma12-048.pdf

(Any fulltext), 2MB

##### Supplementary Material (public)

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##### Citation

Diaz-Polo, J., & Pranzetti, D. (2012). Isolated Horizons and Black Hole Entropy
in Loop Quantum Gravity.* Symmetry, Integrability and Geometry: Methods and Applications (SIGMA),*
*8*: 048. doi:10.3842/SIGMA.2012.048.

Cite as: http://hdl.handle.net/11858/00-001M-0000-000E-EE6A-E

##### Abstract

We review the black hole entropy calculation in the framework of Loop Quantum
Gravity based on the quasi-local definition of a black hole encoded in the
isolated horizon formalism. We show, by means of the covariant phase space
framework, the appearance in the conserved symplectic structure of a boundary
term corresponding to a Chern-Simons theory on the horizon and present its
quantization both in the U(1) gauge fixed version and in the fully SU(2)
invariant one. We then describe the boundary degrees of freedom counting
techniques developed for an infinite value of the Chern-Simons level case and,
less rigorously, for the case of a finite value. This allows us to perform a
comparison between the U(1) and SU(2) approaches and provide a state of the art
analysis of their common features and different implications for the entropy
calculations. In particular, we comment on different points of view regarding
the nature of the horizon degrees of freedom and the role played by the
Barbero-Immirzi parameter. We conclude by presenting some of the most recent
results concerning possible observational tests for theory.