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

追求用于量子信息转换的量子磁振子架构

基本信息

批准号：
18F18015
负责人：
中村泰信
金额：
$ 0.7万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2018
资助国家：
日本
起止时间：
2018-07-25 至 2020-03-31
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-18F18015/
关键词：
Superconducting qubit microwave magnon quantum magnonics superconducting qubit quantum sensing quantum technology

项目摘要

The lifetime of magnons in YIG at millikelvins temperatures is currently limiting the development of quantum magnonics. It had been previously identified that the magnon lifetime is limited by so-called two-levels systems (TLSs) in the ferromagnetic crystal. While the experimental signature of TLSs was observed in 2014, the microscopic origin of these TLSs was still unknown, greatly limiting the ability of researchers to enhance the lifetime of magnons for quantum technologies based on quantum magnonics. An investigation of TLSs in YIG started under the fellowship has led to the discovery that these systems can have very long lifetimes, up to about ten seconds. Such long lifetimes are common for spins in crystals at millikelvin temperatures but had never been observed in a magnetically-ordered crystal. These results provide the first experimental evidence that the TLSs in quantum magnonics are probably spin degrees of freedom of impurities in YIG. Furthermore, we have demonstrated the partial suppression of the relaxation of magnons in the quantum regime. Indeed, thanks to the lifetime of the TLSs being much longer than the lifetime of magnons and superconducting qubits, their contribution to the decay of magnons can be partially suppressed while having both the magnetostatic mode and the qubit very close to their ground state, as required for applications of quantum magnonics.

YIG在Millikelvins温度下的镁寿命目前限制了量子镁的发展。以前已经确定，镁寿命受铁磁晶体中所谓的两级系统（TLSS）的限制。虽然在2014年观察到TLSS的实验特征，但这些TLSS的显微镜起源仍然未知，这极大地限制了研究人员根据量子镁基于量子技术增强量子技术寿命的能力。对YIG的TLSS进行的调查始于研究金，这使发现这些系统的一生可能很长，大约十秒钟。这么长的寿命很常见于毫米温度下的晶体中的旋转，但从未在磁有序的晶体中观察到。这些结果提供了第一个实验证据，表明量子镁的TLSS可能是YIG中杂质自由度的自旋程度。此外，我们已经证明了量子状态下木蛋白松弛的部分抑制。的确，由于TLSS的寿命比少量和超导量子的寿命长得多，因此它们对镁衰减的贡献可以部分抑制，同时具有磁静态模式和量子量非常接近其地面状态，这是量子镁施用所需的所需。