Review Paper on Black Hole

Abstract

Stephen Hawking transformed physics between 1974 and 1975 by positing that black holes have temperature, entropy, and gradually evaporate (Pinochet, 2019). When higher-curvature interactions are considered, a mild version of the weak gravity conjecture (WGC) states that extremal black holes have charge-to-mass ratios greater or equal to one. Because these corrections become more relevant in the low-mass regime, the decay of extremal black holes in terms of energy and charge conservation would be possible. Evidence in this direction has mostly come from corrections to Einstein-Maxwell theory. Corrections to the charge-to-mass ratio of some dyonic extremal black holes explicitly embedded in the heterotic string effective theory are computed here. We discover that the extremality bound changes depending on the solution, with the charge-to-mass ratio remaining constant or deviating positively from one. Furthermore, we observe that the inclusion of higher-curvature terms increases the Wald entropy in all cases considered, and that its variation does not appear to be correlated with the charge-to-mass ratio, contrary to Einstein-Maxwell theory (Cano et al., 2020).