# Outline of Project B02

## Understanding quantum black holes through the study of artificial quantum matter (21H05185)

A black hole gradually evaporates into thermal radiation, which is called the Hawking radiation, and finally disappears. This means that whatever information thrown into a black hole will eventually be “lost”. However, this contradicts the unitary time evolution, with the information on the initial state being conserved, in quantum mechanics. This apparent contradiction is called the “black hole information loss paradox”. Clarifying the mechanism by which information appears to be lost is one of the major objectives of this research area which aims to construct a theory of the “extreme universe” that integrates quantum theory and gravity theory.

The aim of group B02 is to promote the study of the quantum features of black holes, one of the key issues of the “extreme universe”, through the collaboration of cold atom experiments and theoretical studies. According to the gauge–gravity correspondence, the evaporation process of a black hole could correspond to the dynamics of a quantum matter.

Therefore, we will elucidate the nature of black holes by experimentally investigating the non-equilibrium dynamics of cold atomic systems in the laboratory which is a highly-controllable artificial quantum matter.

We will experimentally and theoretically perform research on (I) measurement-induced quantum phase transitions due to the effects of dissipation and/or measurement and (II) out-of-time-ordered correlation as the characterization of the delocalization of quantum information in cold atomic systems. In parallel, we will develop the theory for non-equilibrium phase transitions, methods for calculating non-equilibrium states using quantum computers, and evaluate the quantum entanglement in quantum many-body systems that are thought to correspond to quantum black holes and gauge gravity, such as the Sachdev-Ye-Kitaev model.

### Members in B02

**[Principal Investigator]**

Masaki Tezuka Department of Physics, Kyoto University

**[Co-Investigator]**

Shuta Nakajima Center for Quantum Information and Quantum Biology, Osaka University

Eriko Kaminishi Quantum Computing Center, Keio University

Takashi Mori RIKEN CEMS

Daisuke Yamamoto Department of Physics, Nihon University

**[International Research Collaborators]**

**[ExU Postdoctoral Fellows(Research Collaborators)]**

Kazuya Yamashita Department of Physics, Kyoto University

Giacomo Marmorini Department of Physics, Nihon University

**[Research Collaborators]**

Ippei Danshita Department of Physics, Kindai University

Kazuaki Takasan Department of Physics, University of Tokyo

Juan Pablo Bayona Pena Department of Physics, Kyoto University

**[Graduate Students]**

Kazuki Yamamoto Department of Physics, Kyoto University

Kou Gondaira Graduate School of Science and Engineering, Aoyama Gakuin University