2019 Fiscal Year Research-status Report
Theoretical study of nonlinear optical responses of ultracold atomic systems: towards a high-resolution coherent multidimensional spectroscopy investigation of quantum many-body effects
| Project/Area Number |
19K14638
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| Research Institution | Institute for Molecular Science |
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Principal Investigator |
Nguyen Thanh 分子科学研究所, 理論・計算分子科学研究領域, 助教 (50736337)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | interaction / ultrafast / spectroscopy / nonlinear optics / molecular polariton |
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| Outline of Annual Research Achievements |
Interaction between particles in quantum many-body systems play a crucial role in determining various important physical properties ranging from electric and heat conductivities to magnetism. On the other hand, recent progress in laser pulse techniques has enabled manipulating and measuring physical systems in an ultrafast timescale. In the fiscal year 2019, following the research project plan, I have proposed a new method for direct and ultrafast probe of quantum many-body interaction through the coherent two-dimensional (2D) spectroscopy [1]. I found that the inter-particle interaction manifests itself as off-diagonal cross peaks in the 2D spectroscopy before the whole 2D spectrum contracts into a single diagonal peak as the system approaches the Mott-insulating phase in the strong-interaction regime. This method can be applied to a wide range of interacting quantum many-body systems from ultracold atoms and molecules to strongly correlated electrons.
Furthermore, I have demonstrated the possibility of using the nonlinear optical properties of the hybrid state of light and matter, namely the molecular polariton, which is formed by strongly coupling molecules to an optical cavity, for high-precision measurement of molecular excitation energies [2] and for controlling the nonadiabatic electron-transfer chemical reaction rate [3].
[1] N. T. Phuc and A. Ishizaki (in preparation).
[2] N. T. Phuc and A. Ishizaki, Physical Review Research 1, 033019 (2019).
[3] N. T. Phuc, P. Q. Trung and A. Ishizaki, Scientific Reports 10, 7318 (2020).
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Following the research project plan, in the fiscal year 2019 I calculated the third-order nonlinear optical response of an interacting quantum many-body system, from which the coherent two-dimensional (2D) spectroscopy was constructed. The manifestation of the Mott-insulator phase transition in the coherent 2D spectroscopy was investigated. The dynamics of the quantum many-body system when varying the strength of the interaction and the corresponding evolution of the 2D spectrum were analyzed.
Furthermore, I also studied the nonlinear optical properties of the hybrid state of light and matter, namely the molecular polariton, which is formed by strongly coupling molecules to an optical cavity. These properties were found to be useful for high-precision measurement of molecular excitation energies and for controlling the nonadiabatic electron-transfer chemical reaction rate.
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| Strategy for Future Research Activity |
In the remaining fiscal years 2020 and 2021 of the research project, I plan to study coherent multidimensional spectroscopy in other important quantum many-body systems including Bose-Einstein condensates, fermionic superconductors, and quantum magnets.
I also intend to further explore the nonlinear optical properties of molecular polariton and seek for novel applications of this hybrid state of light and matter.
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| Causes of Carryover |
There is a small amount of money left in this fiscal year, and it will be used in the next fiscal year for the continuing research.
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