On D-Branes and Black Holes in Four Dimensions

TL;DR

This work constructs regular, extremal four-dimensional black holes entirely from intersecting D-branes on $T^6$, enforcing finite dilaton and moduli at the horizon. Microscopic counting is achieved by analyzing bound states of 0-branes at brane intersections, yielding an entropy $S = 2\pi \sqrt{(k/4) Q_1 Q_2 Q_3 Q_4}$ with $k=4$ that reproduces the Bekenstein-Hawking result $S = A/(4G_N)$ for the charges $Q_i$. The counting is supported by an M-theory perspective, which explains bound-state formation and fractional KK contributions, and by dual configurations such as 3-3-3-3 and 2-2-2-6 that share the same entropy structure. The results offer a tractable, soliton-free D-brane realization of 4D black holes with implications for dynamical studies and tests of U-duality and microscopic entropy formulas.

Abstract

We find extremal four dimensional black holes with finite area constructed entirely from intersecting D-branes. We argue that the microscopic degeneracy of these configurations agrees with the Bekenstein-Hawking entropy formula. The absence of solitonic objects in these configurations may make them useful for dynamical studies of black holes.