High-fidelity and robust two-qubit gates for quantum-dot spin qubits in silicon


CH Huang, CH Yang, CC Chen, AS Dzurak, HS Goan

Physical Review A, 99, 042310 (2019)

High-fidelity and robust two-qubit gates for quantum-dot spin qubits in silicon

A two-qubit controlled-not (cnot) gate, realized by a controlled-phase (C-phase) gate combined with single-qubit gates, has been experimentally implemented recently for quantum-dot spin qubits in isotopically enriched silicon, a promising solid-state system for practical quantum computation. In the experiments, the single-qubit gates have been demonstrated with fault-tolerant control fidelity, but the infidelity of the two-qubit C-phase gate is, primarily due to the electrical noise, still higher than the required error threshold for fault-tolerant quantum computation (FTQC). Here, by taking the realistic system parameters and the experimental constraints on the control pulses into account, we construct experimentally realizable high-fidelity cnot gates robust against electrical noise with the experimentally measured 1/f1.01 noise spectrum and also against the uncertainty in the interdot tunnel coupling amplitude. Our fine-tuned optimal cnot gate has about two orders of magnitude improvement in gate infidelity over the ideal C-phase gate constructed without considering any noise effect. Furthermore, within the same control framework, high-fidelity and robust single-qubit gates can also be constructed, paving the way for large-scale FTQC.

University: UNSW Sydney

Authors Centre Participants: Prof. Andrew S. Dzurak

Source: Physical Review A

Publication Type: Refereed Journal article

DOI Link: DOI Link

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