Aurora Method Achieves 97% Improvement in Superconducting Qubit Phase-Coherence Compensation with Offline-Online Control

Maintaining the delicate quantum states of superconducting qubits presents a significant challenge in the development of practical quantum computers, as even small phase fluctuations rapidly degrade computational accuracy. Futoshi Hamanoue, from hi-council. com, and colleagues demonstrate a novel method, termed Aurora-DD, which proactively compensates for these phase errors, substantially improving qubit coherence. The team successfully integrates offline optimisation with real-time hardware implementation, achieving up to 97% improvement in measurement accuracy within a calibrated emulator and validating these results with a 99. 6% reduction in error on actual quantum hardware. This achievement represents a crucial step towards building more stable and reliable near-term quantum devices, offering a practical solution for mitigating phase-related errors in single-qubit settings.

Dynamic Phase Compensation Enhances Qubit Performance

This work details the development and validation of Aurora-DD, a closed-loop phase compensation technique designed to improve the performance of noisy intermediate-scale quantum (NISQ) devices. Aurora-DD actively compensates for phase errors in qubits by dynamically adjusting control pulses, unlike traditional open-loop techniques. The method combines effectively with existing techniques like XY8 dynamical decoupling, enhancing their effectiveness, and utilizes a computationally efficient sign-based update rule suitable for implementation on platforms like FPGAs. Results demonstrate a 99. 2-99.

6% reduction in absolute error on both simulated and real IBM quantum hardware, showcasing consistent performance and stability even with device drift, shot noise, and calibration imperfections. Combining Aurora-DD with Zero-Noise Extrapolation (ZNE) proved detrimental, amplifying noise and introducing instability. Future research directions include extending the technique to multi-qubit systems, implementing real-time adaptive control, deploying Aurora-DD on FPGAs, integrating it with variational algorithms, and exploring its potential as a building block for future error correction schemes. This research presents a compelling case for closed-loop phase compensation as a practical technique for more robust and reliable quantum computation.

Offline Calibration Boosts Quantum Phase Coherence

Researchers developed Aurora-DD, a protocol combining a closed-loop optimized phase offset with a fixed-depth XY8 dynamical decoupling sequence, demonstrating a significant advancement in phase-coherence compensation for NISQ devices. The core innovation lies in optimizing the phase correction offline using a calibrated emulator, then applying it as a pre-calibrated offset on actual hardware, effectively bridging the gap between closed-loop control and open-loop implementation. Extensive emulator testing revealed substantial improvements in measurement accuracy, achieving a 68-97% reduction in the mean-squared error of the measured expectation value, demonstrating the controller’s effectiveness in suppressing both dephasing and systematic phase bias under calibrated noise conditions. Validation on IBM’s superconducting hardware further confirmed these findings, yielding point estimates corresponding to approximately 99.

2-99. 6% reduction in absolute error relative to an unmitigated baseline. This hardware data supports the practical viability of pre-calibrated Aurora-DD as a stable and hardware-compatible phase-coherence compensator for single-qubit settings.

Aurora-DD Stabilizes Quantum Coherence to 99. 6%

The team has demonstrated a significant advancement in maintaining quantum coherence through Aurora-DD, a phase-coherence compensation technique integrated with standard dynamical decoupling. Experiments using both calibrated emulators and real superconducting quantum hardware reveal substantial reductions in error, achieving up to 99. 6% reduction in absolute error across multiple phase settings. This improvement stems from Aurora-DD’s ability to suppress both dephasing and systematic phase bias, offering a stable and practical approach for near-term quantum devices. Future work includes extending Aurora-DD to multi-qubit systems and entangling gates, integrating real-time adaptive control, and exploring FPGA-based implementations. The team intends to leverage multi-backend quantum simulators to investigate Aurora-DD under a wider range of noise models and device abstractions, focusing on deeper circuits and application-level workloads.