Abstract

Electron spins confined in quantum dots are an attractive system to realize high-fidelity qubits owing to their long coherence time. With the prolonged spin coherence time, however, the control fidelity can be limited by systematic errors rather than decoherence, making characterization and suppression of their influence crucial for further improvement. Here we report that the control fidelity of Si/SiGe spin qubits can be limited by the microwave-induced frequency shift of electric dipole spin resonance and it can be improved by optimization of control pulses. As we increase the control microwave amplitude, we observe a shift of the qubit resonance frequency, in addition to the increasing Rabi frequency. We reveal that this limits control fidelity with a conventional amplitude-modulated microwave pulse below 99.8%. In order to achieve a gate fidelity >99.9%, we introduce a quadrature control method, and validate this approach experimentally by randomized benchmarking. Our finding facilitates realization of an ultra-high-fidelity qubit with electron spins in quantum dots.

Details

Title
Optimized electrical control of a Si/SiGe spin qubit in the presence of an induced frequency shift
Author
Takeda, K 1   VIAFID ORCID Logo  ; Yoneda, J 1   VIAFID ORCID Logo  ; Otsuka, T 2 ; Nakajima, T 1   VIAFID ORCID Logo  ; Delbecq, M R 3   VIAFID ORCID Logo  ; Allison, G 1 ; Hoshi, Y 4 ; Usami, N 5 ; Itoh, K M 6 ; Oda, S 7 ; Kodera, T 8 ; Tarucha, S 9 

 RIKEN, Center for Emergent Matter Science (CEMS), Saitama, Japan 
 RIKEN, Center for Emergent Matter Science (CEMS), Saitama, Japan; JST, PRESTO, Saitama, Japan; Research Institute of Electrical Communication, Tohoku University, Sendai, Japan 
 RIKEN, Center for Emergent Matter Science (CEMS), Saitama, Japan; Laboratoire Pierre Aigrain, Ecole Normale Supérieure-PSL Research University, CNRS, Université Pierre et Marie Curie-Sorbonne Universités, Université Paris Diderot-Sorbonne Paris Cité, Paris Cedex 05, France 
 Advanced Research Laboratories, Tokyo City University, Tokyo, Japan 
 Graduate School of Engineering, Nagoya University, Nagoya, Japan 
 Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, Japan 
 Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, Tokyo, Japan 
 Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, Tokyo, Japan 
 RIKEN, Center for Emergent Matter Science (CEMS), Saitama, Japan; Department of Applied Physics, The University of Tokyo, Tokyo, Japan 
Pages
1-6
Publication year
2018
Publication date
Oct 2018
Publisher
Nature Publishing Group
e-ISSN
20566387
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2126883356
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.