{"title":"Quantum sensing with duplex qubits of silicon vacancy centers in SiC at room temperature","authors":"Kosuke Tahara, Shin-ichi Tamura, Haruko Toyama, Jotaro J. Nakane, Katsuhiro Kutsuki, Yuichi Yamazaki, Takeshi Ohshima","doi":"10.1038/s41534-025-01011-2","DOIUrl":null,"url":null,"abstract":"<p>The silicon vacancy center in Silicon Carbide (SiC) provides an optically addressable qubit at room temperature in its spin-<span>\\(\\frac{3}{2}\\)</span> electronic state. However, optical spin initialization and readout are less efficient compared to those of spin-1 systems, such as nitrogen-vacancy centers in diamond, under non-resonant optical excitation. Spin-dependent fluorescence exhibits contrast only between <span>\\(| m=\\pm 3/2\\left.\\right\\rangle\\)</span> and <span>\\(| m=\\pm 1/2\\left.\\right\\rangle\\)</span> states, and optical pumping does not create a population difference between <span>\\(| +1/2\\left.\\right\\rangle\\)</span> and <span>\\(| -1/2\\left.\\right\\rangle\\)</span> states. Thus, operating one qubit (e.g., <span>\\(\\left\\{| +3/2\\left.\\right\\rangle ,| +1/2\\left.\\right\\rangle \\right\\}\\)</span> states) leaves the population in the remaining state (<span>\\(| -1/2\\left.\\right\\rangle\\)</span>) unaffected, contributing to background in optical readout. To mitigate this problem, we propose a sensing scheme based on duplex qubit operation in the quartet, using microwave pulses with two resonant frequencies to simultaneously operate <span>\\(\\left\\{| +3/2\\left.\\right\\rangle ,| +1/2\\left.\\right\\rangle \\right\\}\\)</span> and <span>\\(\\left\\{| -1/2\\left.\\right\\rangle ,| -3/2\\left.\\right\\rangle \\right\\}\\)</span>. Experimental results demonstrate that this approach doubles signal contrast in optical readout and improves sensitivity in AC magnetometry compared to simplex operation.</p>","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"16 1","pages":""},"PeriodicalIF":6.6000,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"npj Quantum Information","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1038/s41534-025-01011-2","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
The silicon vacancy center in Silicon Carbide (SiC) provides an optically addressable qubit at room temperature in its spin-\(\frac{3}{2}\) electronic state. However, optical spin initialization and readout are less efficient compared to those of spin-1 systems, such as nitrogen-vacancy centers in diamond, under non-resonant optical excitation. Spin-dependent fluorescence exhibits contrast only between \(| m=\pm 3/2\left.\right\rangle\) and \(| m=\pm 1/2\left.\right\rangle\) states, and optical pumping does not create a population difference between \(| +1/2\left.\right\rangle\) and \(| -1/2\left.\right\rangle\) states. Thus, operating one qubit (e.g., \(\left\{| +3/2\left.\right\rangle ,| +1/2\left.\right\rangle \right\}\) states) leaves the population in the remaining state (\(| -1/2\left.\right\rangle\)) unaffected, contributing to background in optical readout. To mitigate this problem, we propose a sensing scheme based on duplex qubit operation in the quartet, using microwave pulses with two resonant frequencies to simultaneously operate \(\left\{| +3/2\left.\right\rangle ,| +1/2\left.\right\rangle \right\}\) and \(\left\{| -1/2\left.\right\rangle ,| -3/2\left.\right\rangle \right\}\). Experimental results demonstrate that this approach doubles signal contrast in optical readout and improves sensitivity in AC magnetometry compared to simplex operation.
期刊介绍:
The scope of npj Quantum Information spans across all relevant disciplines, fields, approaches and levels and so considers outstanding work ranging from fundamental research to applications and technologies.