2018 Fiscal Year Annual Research Report
量子情報変換に向けた量子マグノニクスアーキテクチャの追求
| Project/Area Number |
18F18015
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| Research Institution | The University of Tokyo |
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Principal Investigator |
中村 泰信 東京大学, 先端科学技術研究センター, 教授 (90524083)
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| Co-Investigator(Kenkyū-buntansha) |
LACHANCE-QUIRION DANY 東京大学, 先端科学技術研究センター, 外国人特別研究員
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| Project Period (FY) |
2018-07-25 – 2020-03-31
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| Keywords | quantum magnonics / superconducting qubit / quantum sensing / quantum technology |
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| Outline of Annual Research Achievements |
During FY2018, I have performed a set of novel experiments in the field of quantum magnonics, in which modes of collective spin excitations in a ferromagnetic crystal are interacting coherently with a superconducting qubit. These experiments were enabled by our ability to perform time-resolved experiments in the microwave domain in quantum magnonics thanks to a new and versatile experimental platform me and a research student put together at the beginning of FY2018. In a first set of experiments, we have performed tomography measurements of magnon vacuum and coherent states, enabling us to study the dynamics of magnons in the quantum regime. These experiments constitute a first step towards the preparation and characterization of quantum states of magnons. In a second set of experiments, we have demonstrated single-shot detection of a single magnon with an efficiency reaching 70% by using an entangling operation between a collective spin-wave mode and the superconducting qubit. Finally, in a third set of experiments, we have demonstrated a quantum sensing protocol with a magnon detection sensitivity of 10-3 magnons/√Hz. Thanks to these results, I have made during FY2018 nine oral presentations, with three of these being at international conferences and one being an invited oral presentation, as well as being the first author of an invited review paper for Applied Physics Express for publication in FY2019 (arXiv:1902.03024).
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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
The focus of our research has shifted slightly for FY2018 from developing a quantum transducer based on magnonics to demonstrating different quantum sensing protocols in quantum magnonics. This change of focus has enabled us to expand our knowledge about the physics at play for developing quantum transducers based on magnonics as well as enabling us to produce, on a short term, a greater research output. Indeed, we currently have two manuscript in preparation for submissions to high-impact journals based on the results obtained in FY2018. These progresses should furthermore enable us to still demonstrate novel results in FY2019 as we have just started to explore the new subject of quantum sensing of magnons. Therefore, despite the temporary change of focus, we feel the progress made in FY2018 is significant and should only help us for further progress in the future.
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| Strategy for Future Research Activity |
Improvements of the hybrid quantum device used in FY2018 are primordial to further progress towards our goal to encode and decode quantum information in a ferromagnetic crystal for quantum transduction. For these reasons, the focus for the future work will lie in the development of a new hybrid quantum system for quantum magnonics that should enable us to reach the desired parameters. This new hybrid device will feature a three-dimensional lumped-element cavity to increase the coupling between the cavity and magnetostatic modes. Furthermore, internal losses will be reduced by using a superconducting material for the cavity while satisfying the constraint set by the requirement of an external magnetic field being applied to the ferromagnetic crystal. The design of the hybrid system will be optimized through finite-element simulations, as well as numerical and analytical simulations of open quantum systems. With this optimized hybrid device, we should be able to demonstrate the deterministic encoding of an arbitrary state of a superconducting qubit into a nonclassical state of magnons, a primordial step towards the quantum transduction based on magnonics.
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Research Products
(6 results)
