2021 Fiscal Year Research-status Report
Magnons for quantum information
| Project/Area Number |
21K13847
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| Research Institution | Tohoku University |
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Principal Investigator |
ELYASI MEHRDAD 東北大学, 材料科学高等研究所, 特任助教 (30840326)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | Magnons / Quantum information / Stochastic switching / Nonlinearity / Parametric excitation |
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| Outline of Annual Research Achievements |
We theoretically explained the experimentally observed stochastic switching (“p-bit” characteristics) of the Ising pseudo-spin of parametrically excited spin waves formed at room temperature. We explained it based on an instability of the uniform magnetization precession in the nonlinear regime which was published as Phys. Rev. B 105, 054403 (2022). We also predicted a dynamical phase of the parametrically excited magnons, which at lower temperatures is quantum correlated with significant distillible magnon entanglement useful for quantum information [arXiv:2111.00365]. These results on the nonlinear parametrically excited magnons can lead to unconventional computing schemes that may supersede conventional computing paradigms.
I have also formed several experimental collaborations on nonlinearity of magnons and have developed theory for several recent experimental observations [e.g. arXiv:2201.10889]. For example, I have explained a reduction in dissipation of the uniform spin wave mode as a result of its three-magnon instability to a pair of magnons with low dissipation rates, which has been observed by Prof. Eiji Saitoh group (Univ. of Tokyo) [manuscript in preparation].
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
I could make a significant theoretical progress based on the proposed project, and explored the nonlinearity of magnons for both quantum information and stochastic computing.
The collaborations with experimental groups on magnon nonlinearities for different applications are exceeding the expectations. Several experimental manuscripts with a theoretical support from me are in preparation for submission to high impact journals. Based on these collaborations, I have further expanded my studies on effects of magnon nonlinearity to magnetometry using nitrogen vacancy centers spins [Toeno van der Sar group, TU Delft], chiral spin wave excitations using magnetic nanowires [Haiming Yu group, Beihang Univ.], and stochastic magnetic tunnel junctions [Shunsuke Fukami group, Tohoku Univ.].
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| Strategy for Future Research Activity |
I will theoretically characterize the spintronics based magnon tomography developed by Eiji Saitoh group (Univ. of Tokyo) for detection and implementation of the predicted quantum entanglement between the parametrically excited uniform magnon mode and a pair of large wavenumber magnons.
I will finalize manuscripts for submission to Phys. Rev. journal on theories developed for chirally excited nonlinear magnons, frequency combing by four-magnon interactions for wideband magnetometry using quantum spins, and reduction in dissipation of spin waves by their instability to low dissipation magnons.
I will also theoretically investigate cavities for THz frequency light strongly coupling to 2D THz magnons. For this purpose, I will investigate hyperbolic metamaterials to achieve strong coupling.
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| Causes of Carryover |
This amount will be used to attend a workshop which I am co-organzing at Max-Planck Institute, Erlangen, Germany, Dec. 2022, combined with a two-weeks research visit to that institute.
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Research Products
(3 results)
