2023 Fiscal Year Final Research Report
Theoretical study on quantum bit in strongly correlated systems
| Project/Area Number |
19K03708
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | 近藤効果 / 量子ビット / 量子多体効果 |
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| Outline of Final Research Achievements |
In this study, we revealed that when there are multiple localized spins that interact with itinerant electrons, a multistage Kondo effect occurs in which the itinerant electrons are sequentially bound one by one by the multiple localized spins. This discontinuous change in the number of bound electrons greatly changes the quantum correlation between local spins, so by adjusting the strength of the coupling between itinerant electrons and localized spins, it becomes possible to control the quantum state of localized spins. In particular, transitions to various quantum states occur by adjusting the configuration of localized spins and the density of itinerant electrons. It was revealed that the multistage Kondo effect produced by multiple localized spins and itinerant electrons greatly expands the conventional concept of the Kondo effect.
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| Free Research Field |
物性物理学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究が明らかにした多段の近藤効果は、遍歴電子と局在スピンの間の電位差を制御することで、局在スピンと遍歴電子の間で量子状態の組み換えを逐次的に引き起こすという、電圧印可による局在スピン間の量子相関の制御を可能にする技術的意義を有している。また、この多段の近藤効果は、遍歴電子と局在スピンがスピン一重項を形成して局在スピンの磁性が消失する従来の近藤効果とは全く異なり、局在スピンの空間配置と遍歴電子の密度に応じた様々な量子状態間の遷移を可能にする多彩な量子的遷移を生み出す新たな物性現象としての学術的な意義も有している。
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