# Outline of Project C01

## Quantum Cosmology from Quantum Information (21H05187)

The geometric formula of entanglement entropy (Ryu-Takayanagi formula), which connects quantum information and gravity theory, has led to the prediction that the universe in gravitational theory is a collection of quantum information, which has attracted worldwide attention. The aim of group C01 is to develop this prediction by introducing the viewpoint of quantum information into high energy theory, and to uncover the basic theory of the "dynamics of the creation of the universe (quantum universe)," which is one of the three problems of extreme universe. The foundation for this is the "gauge-gravity correspondence," or the hypothesis that the gravitational theory of the anti de Sitter universe is equivalent to a theory of quantum many-body system. The gauge-gravity correspondence is a powerful idea that has passed enormous verifications, but the basic principle of why this correspondence arises still remains unknown. If this principle is understood completely, it will be possible to elucidate the mechanism of the creation of the universe from nothing and eventually to construct the ultimate physical laws. The anti-de Sitter universe is a universe with negative curvature, while the real universe we live in and the process of creation of the universe are thought to have positive curvature, i.e., a de Sitter universe. In this research, we will first clarify the basic principle of gauge-gravity correspondence by combining the methods of quantum information theory and gauge-gravity correspondence, and then use it as a hint to extend the gauge-gravity correspondence beyond the anti-de Sitter universe to more general universes including the de Sitter universe. This will finally provide us with the fundamental theory for quantum cosmology.

### Members in C01

**[Principal Investigator]**

Tadashi Takayanagi Yukawa Institute for Theoretical Physics, Kyoto University

**[Co-Investigator]**

Yasuaki Hikida Yukawa Institute for Theoretical Physics, Kyoto University

Kazumi Okuyama Faculty of Science, Shinshu University

Yasuhiro Sekino Faculty of Engineering, Takushoku University

Shigeki Sugimoto Department of Physics, Kyoto University

**[International Research Collaborators]**

Shinsei Ryu Princeton U., USA

Beni Yoshida Perimeter Institute, Canada

**[ExU Postdoctoral Fellows(Research Collaborators)]
**Jonathan Harper Yukawa Institute for Theoretical Physics, Kyoto University

**[Research Collaborators]**

Kanato Goto Yukawa Institute for Theoretical Physics, Kyoto University

Tomotaka Kitamura Institute of Theoretical Physics, Rikkyo University

Shoichiro Miyashita Graduate School of Advanced Science and Engineering, Waseda University

Kazuhiro Sakai Institute of Physics, Meiji Gakuin University

Takahiro Uetoko National Institute of Technology, Kushiro College

Masamichi Miyaji Institute for Advanced Research, Nagoya University

Kenta Suzuki Institute of Theoretical Physics, Rikkyo University

Shan-Ming Ruan Yukawa Institute for Theoretical Physics, Kyoto University

Ali Mollabashi IPM - Institute for Research in Fundamental Sciences, Iran

Pawel Caputa Warsaw University

Zixia Wei Harvard University

Takato Mori Yukawa Institute for Theoretical Physics, Kyoto University

**[Graduate Students]**

Yusuke Taki Yukawa Institute for Theoretical Physics, Kyoto University

Taishi Kawamoto Yukawa Institute for Theoretical Physics, Kyoto University

Naoki Ogawa Yukawa Institute for Theoretical Physics, Kyoto University

Yu-ki Suzuki Yukawa Institute for Theoretical Physics, Kyoto University

Takashi Tsuda Yukawa Institute for Theoretical Physics, Kyoto University

Kazuki Doi Yukawa Institute for Theoretical Physics, Kyoto University

Hiroki Kanda Yukawa Institute for Theoretical Physics, Kyoto University

Masahide Sato Yukawa Institute for Theoretical Physics, Kyoto University

Kotaro Shinmyo Yukawa Institute for Theoretical Physics, Kyoto University

Kenya Tasuki Yukawa Institute for Theoretical Physics, Kyoto University

**[Past Members]
**Ibrahim Akal Yukawa Institute for Theoretical Physics, Kyoto University

**Yoshiki Sato Yukawa Institute for Theoretical Physics, Kyoto University**