Quantum entanglement phenomena in organic massless Dirac electron systems

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K18739
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: Toho University
• Principal Investigator: TAJIMA Naoya 東邦大学, 理学部, 教授 (40316930)
• Co-Investigator(Kenkyū-buntansha): 西尾 豊 東邦大学, 理学部, 教授 (20172629) ; 森成 隆夫 京都大学, 人間・環境学研究科, 教授 (70314284) ; 須田 理行 分子科学研究所, 協奏分子システム研究センター, 助教 (80585159)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Keywords: 有機ディラック電子系 / エンタングルメント / ランダウ準位交差 / アクシオン

Outline of Final Research Achievements

Entanglement plays an important role to the development of quantum computers. The technique has developed in the quantum optics field mainly. In this study, we tried the creation of the entanglement in the organic Dirac electron systems in the magnetic field at low temperature. The controls of the field strength, the field angle and the Fermi level causes the level crossing of Landau levels. The spin and the valley splitting energies of the Landau levels is nearly equal in this system. Thus, it was expected that the split Landau levels were entangled complicatedly at the vicinity of level crossing.
In this study, we demonstrated theoretically that the entanglement entropy became highest at the vicinity of Landau level crossing. On the other hand, the characteristic feature could not be detected in the experiments of the quantum transport and the specific heat. However, we could find a new physical phenomenon. The broken chiral symmetry gave rise to axion electromagnetic responses.

Free Research Field

固体物性

Academic Significance and Societal Importance of the Research Achievements

固体中に量子エンタングルメントの生成・検出の成功例は、Si半導体を利用した研究のみである。ランダウ準位準位交差に着目した前例はなく、本研究の成果は、固体物理学、デバイス物理学、量子情報科学などへの波及効果は非常に大きい。一方、アクシオンを固体中に生成できれば、静磁場で静電場を、静電場で静磁場を誘起でき、基礎研究のみならず低消費電力デバイス開発が期待される。アクシオンが存在する物質探索・物質創成には大きな意義がある。