Universal physics of quantum matter for the state change and the phase change

2022 Fiscal Year Final Research Report

• Project Area: Clustering as a window on the hierarchical structure of quantum systems
• Project/Area Number: 18H05406
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2019-2021); The University of Tokyo (2018)
• Principal Investigator: Munekazu Horikoshi 大阪公立大学, 南部陽一郎物理学研究所, 特任准教授 (00581787)
• Co-Investigator(Kenkyū-buntansha): 大橋 洋士 慶應義塾大学, 理工学部(矢上), 教授 (60272134) ; 田島 裕之 東京大学, 大学院理学系研究科(理学部), 助教 (80804278) ; 飯田 圭 高知大学, 教育研究部自然科学系理工学部門, 教授 (90432814)
• Project Period (FY): 2018-06-29 – 2023-03-31
• Keywords: 冷却原子実験 / フェルミ粒子系 / 量子多体系 / 物性物理 / 原子核物理 / レーザー冷却 / 量子シミュレータ / 量子エレクトロニクス

Outline of Final Research Achievements

In response to the question "How does the transition occur between layers of matter?", we deepened universal fundamental physics in the hierarchy of matter both experimentally and theoretically by using ultracold atomic Fermi gases, which have controllable attractive interactions. It was shown that the boundary between the atomic and molecular hierarchies can be estimated from the equation of state for the shear viscosity. It was also clarified that the equation of state for the isothermal compressibility is significantly affected by the three-body interaction between molecules. We pointed out that these interpretations are equally applicable to the Quark-gluon plasma (between quark hierarchy and hadron hierarchy). In addition, we suggested that the nuclear diagram could be modified by the medium effect in neutron matter with high density, and the possibility of hadron-quark crossover in the ternary fermion system.

Free Research Field

冷却原子実験

Academic Significance and Societal Importance of the Research Achievements

量子的な粒子が多数存在する量子多体系において、①基本粒子が複合粒子に変化する際に何の観測量が敏感に応答するのか、②その際に粒子間相互作用が複合粒子間相互作用に変化する様子は何の観測量に現れるか、③また孤立系と多体系では複合粒子に変化する様子がどのように異なるのか、それらについての基礎物理を深化させた。これらの知見は、クオーク・グルーオンプラズマ状態からクオークが閉じ込められハドロンに変化する過程、クオーク間力からの核力の説明、原子核内のα粒子間相互作用、中性子星内の核物質の理解を加速させるものである。さらにそれら理論提案を検証する冷却原子を用いた量子多体シミュレータを開発した。