Mid-circuit correction of correlated phase errors using an array of spectator qubits

Area of Science:

• Quantum Computing
• Atomic Physics

Background:

• Scaling quantum processors is challenging due to inherent errors.
• Quantum error correction requires significant qubit overhead and faces strict error thresholds.
• Auxiliary spectator qubits offer a complementary approach for in situ noise probing and real-time error correction.

Purpose of the Study:

• To demonstrate a novel protocol for correcting correlated phase errors in quantum processors using spectator qubits.
• To establish key tools for scaling neutral-atom quantum processors.

Main Methods:

• Utilized an array of cesium spectator qubits to monitor and correct errors on an array of rubidium data qubits.
• Implemented a system combining in-sequence readout, data processing, and feedforward operations for real-time error correction.
• Developed mid-circuit readout, real-time processing, and coherent mid-circuit qubit reloading techniques for neutral-atom arrays.

Main Results:

• Successfully suppressed correlated phase errors within the execution of a quantum circuit.
• Demonstrated the efficacy of spectator qubits in correcting data qubit errors in real-time.
• Validated the broad applicability of the protocol across different quantum information platforms.

Conclusions:

• The developed protocol provides a viable strategy for mitigating errors in quantum computing.
• The established tools are crucial for advancing the scalability of neutral-atom quantum processors.
• This work offers a promising path towards fault-tolerant quantum computation.