Quantum improved black holes in asymptotic safety and thermodynamics


2022/07/07 15:00 – 16:00




石橋 明浩 教授 (近畿大学)





酒井 勝太/sakaika-AT-post.kek.jp


We discuss quantum improvements of black holes in asymptotic safety scenario. In this scenario, the Newton coupling depends on an energy scale, which must then be identified with a certain length scale. Due to this “scale identification,” in a small scale, e.g., near the singularity, a quantum mechanically corrected or “quantum improved” geometry behaves significantly differently from its classical counterpart. For example, the quantum improved Schwarzschild black hole is perfectly regular near the center. However, when considering more general black holes, whether a singularity is resolved or not depends on the choice of possible scale identification. Furthermore, if applying the same scale identification as in the Schwarzschild case for a rotating black hole, the quantum improved rotating black hole becomes inconsistent with the thermodynamic laws. In this talk, we first briefly review quantum improvement of black holes in asymptotic safety scenario and the problem in possible choice of scale identifications. We then propose that the consistency with the first law of black hole thermodynamics is the guiding principle for a physically sensible choice of scale identifications. This principle leads us to show that the running Newton coupling should be a function of the horizon area at least near the horizon, and also to find a universal formula for the quantum entropy.