Real-time feedback protocols for optimizing fault-tolerant two-qubit gate fidelities in a silicon spin system

Abstract

Recently, several groups have demonstrated two-qubit gate fidelities in semiconductor spin qubit systems above 99%. Achieving this regime of fault-tolerant compatible high fidelities is nontrivial and requires exquisite stability and precise control over the different qubit parameters over an extended period of time. This can be done by efficiently calibrating qubit control parameters against different sources of micro- and macroscopic noise. Here, we present several single- and two-qubit parameter feedback protocols, optimised for and implemented in state-of-the-art fast FPGA hardware. Furthermore, we use wavelet-based analysis on the collected feedback data to gain insight into the different sources of noise in the system. Scalable feedback is an outstanding challenge and the presented implementation and analysis gives insight into the benefits and drawbacks of qubit parameter feedback, as feedback related overhead increases. This work demonstrates a pathway towards robust qubit parameter feedback and systematic noise analysis, crucial for mitigation strategies towards systematic high-fidelity qubit operation compatible with quantum error correction protocols.

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Cited by in corpus (9)

• Assessment of error variation in high-fidelity two-qubit gates in silicon
• A 300 mm foundry silicon spin qubit unit cell exceeding 99% fidelity in all operations
• Violating Bell's inequality in gate-defined quantum dots
• Passive and active suppression of transduced noise in silicon spin qubits
• Automation of Quantum Dot Measurement Analysis via Explainable Machine Learning
• Real-time adaptive tracking of fluctuating relaxation rates in superconducting qubits
• Efficient Qubit Calibration by Binary-Search Hamiltonian Tracking
• Interplay of Zeeman Splitting and Tunnel Coupling in Coherent Spin Qubit Shuttling
• Wavelet correlation noise analysis for qubit operation variable time series