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An addressable quantum dot qubit with fault-tolerant control-fidelity
M Veldhorst1, J C C Hwang1, C H Yang1
1Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia.
Nature Nanotechnology
|October 13, 2014
Summary
Researchers developed a new quantum dot qubit in silicon, achieving 99.6% control fidelity. This breakthrough offers long coherence times and precise control, paving the way for scalable quantum computing.
Area of Science:
- Quantum Computing
- Semiconductor Physics
- Materials Science
Background:
- Spin-based quantum computing utilizes nitrogen-vacancy centers in diamond and phosphorus in silicon qubits.
- Challenges remain in qubit coupling and individual addressing for single-atom nanotechnologies.
- Quantum dots offer engineered coupling but suffer from noise-induced dephasing and low fidelities.
Purpose of the Study:
- To combine the advantages of different spin qubit schemes.
- To demonstrate a high-fidelity, gate-addressable quantum dot qubit in isotopically engineered silicon.
Main Methods:
- Utilized isotopically engineered silicon for quantum dot fabrication.
- Employed Clifford-based randomized benchmarking to assess control fidelity.
- Investigated gate-voltage tuning of the electron g*-factor for Stark shifting resonance frequency.
Main Results:
- Achieved a control fidelity of 99.6%, meeting requirements for fault-tolerant quantum computing.
- Demonstrated a dephasing time (T2*) of 120 μs and coherence time (T2) of 28 ms.
- Showcased Stark shift of electron spin resonance frequency exceeding 3,000 times the linewidth.
Conclusions:
- The developed quantum dot qubit in silicon combines high fidelity and long coherence times.
- Gate-voltage tunability enables individual addressing for large-scale qubit arrays.
- The technology is compatible with existing semiconductor manufacturing, facilitating scalable quantum computing.
