| Project/Area Number |
18K19065
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
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| Research Institution | Nihon University |
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Principal Investigator |
SAKO Tokuei 日本大学, 理工学部, 准教授 (60361565)
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| Project Period (FY) |
2018-06-29 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2018: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | 光物質相互作用 / 放射反作用 / マックスウェル方程式 / シュレディンガー方程式 / 分極電流密度 / 電子波束 / 縦波・横波 / レーザー場 / シンプレクティック積分法 / 電子相関 / 振動子強度 / スピン分極 / 共鳴トンネリング / 自己相互作用 / 時間領域差分法 / ナノ物質 |
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| Outline of Final Research Achievements |
The polarization current density that is the key quantity to couple Maxwell's equations and the time-dependent Schroedinger equation was analyzed to establish a reliable computational method for light-matter interaction that takes into account the radiation reaction. The polarization current density in the real space derived from the equation of continuity for the electron density involves both longitudinal and transverse components, and it is necessary to eliminate the longitudinal component corresponding to the Coulomb self-interaction. As an illustrative example, we focused on a system of an electron confined in a quasi-one-dimensional nanostructure and subjected to a pulsed laser field and separated the longitudinal and transverse components by the orthogonality condition with the wavenumber vector in the reciprocal space. The results show an appreciable change in the ratio between the transverse and longitudinal components for different strength of the lateral confinement.
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| Academic Significance and Societal Importance of the Research Achievements |
光物質相互作用を扱う従来の理論モデルでは「電子系の励起による入射電磁場の変形」は小さいと仮定して無視し，そのため電磁場は電子系の励起とは無関係に a prioriに決まった変化をする時間依存ポテンシャルとして扱われてきた．近年，近接場を利用した顕微分光に代表されるように，物質の光励起によって局所的に生成する強力な電磁場が物性に与える影響に大きな注目が集まっている．このため「電子系による電磁場への反作用」を取り入れた本理論モデルの構築および計算方法の開発は，今後更なる実験の進展によって重要性が増すと考えられる．
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