# Outline of Project B01

## Quantum Black Holes from Quantum Information (21H05184)

Black Holes are probably the most mysterious and interesting objects in the universe. Classically due to their strong gravitational forces, once you enter through the black hole horizon, you can never go out. However if one considers the quantum effects, this is not true anymore. In fact a black hole has definite temperature and radiates thermally (which is so-called Hawking radiation). Furthermore, a black hole has huge entropy, suggesting that a black hole is in fact a coarse-grained description of degenerate states, whose degeneracy is given by exponential of the entropy, according to the Boltzmann’s entropy formula. These suggest that one should also have a fine-grained description of gravity, which is quantum gravity and string theory is the most successful candidate for it. Recent studies show that two important concepts play an important role in understanding quantum gravity/string theory. One is quantum information. The other is gauge/string duality, which claims that certain quantum gravity is equivalent to certain gauge theory. Our main research goal is using these two important concepts, to understand the physics behind the horizon of quantum black holes, and how quantum mechanics is consistent with gravity. More concretely we would like to figure out the answer for the following key questions; how the physical information of the black hole leaks out through the Hawking radiation? How quantum gravity corrects Hawking’s mistake? What are the laws of physics behind the black hole horizon? Through the study of quantum black holes, we would like to understand the basic principles for quantum gravity.

### Members in B01

**[Principal Investigator]**

Norihiro Iizuka Department of Physics, Osaka University

**[Co-Investigator]**

Toshifumi Noumi Department of Physics, Kobe University

Masaki Shigemori Department of Physics, Nagoya University

Seiji Terashima Yukawa Institute for Theoretical Physics, Kyoto University

Tomonori Ugajin The Hakubi Center for Advanced Research, Kyoto University

**[ExU Postdoctoral Fellows(Research Collaborators)]
**Sunil Kumar Sake Department of Physics, Osaka University

**[Research Collaborators]**

Kotaro Tamaoka College of Humanities and Sciences Department of Physics, Nihon University

Koji Hashimoto Department of Physics, Kyoto University

Kengo Maeda Faculty of Engineering, Shibaura Institute of Technology

**[Graduate Students]**

Takanori Anegawa Department of Physics, Osaka University