Entropy in Black Hole Pair Production
D. Garfinkle, S. B. Giddings, A. Strominger
TL;DR
Pair production of Reissner-Nordstroem black holes in a magnetic field can be described by a Euclidean instanton and it is shown that the instanton amplitude contains an explicit factor that is consistent with the hypothesis that [ital e][sup [ital A]/4] measures the number of black hole states.
Abstract
Pair production of Reissner-Nordstrom black holes in a magnetic field can be described by a euclidean instanton. It is shown that the instanton amplitude contains an explicit factor of $e^{A/4}$, where $A$ is the area of the event horizon. This is consistent with the hypothesis that $e^{A/4}$ measures the number of black hole states.