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Journal Articles EPL - Europhysics Letters Year : 2014

Black-hole entropy from complex Ashtekar variables


In loop quantum gravity, the number $N_\Gamma(A,\gamma)$ of microstates of a black hole for a given discrete geometry $\Gamma$ depends on the so-called Barbero-Immirzi parameter $\gamma$. Using a suitable analytic continuation of $\gamma$ to complex values, we show that the number $N_\Gamma(A,\pm i)$ of microstates behaves as $\exp(A/(4\ell_\text{Pl}^2))$ for large area $A$ in the large spin semiclassical limit. Such a correspondence with the semiclassical Bekenstein-Hawking entropy law points towards an unanticipated and remarkable feature of the original complex Ashtekar variables for quantum gravity.

Dates and versions

hal-00957634 , version 1 (10-03-2014)



E. Frodden, M. Geiller, K. Noui, A. Perez. Black-hole entropy from complex Ashtekar variables. EPL - Europhysics Letters, 2014, 107 (1), ⟨10.1209/0295-5075/107/10005⟩. ⟨hal-00957634⟩
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