Probabilistic error cancellation with sparse Pauli–Lindblad models on noisy quantum processors

• Published in: Nature physics Vol. 19; no. 8; pp. 1116 - 1121
• Main Authors: van den Berg, Ewout, Minev, Zlatko K., Kandala, Abhinav, Temme, Kristan
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2023; Nature Publishing Group
• Subjects: 639/766/483; 639/766/483/481; Atomic; Cancellation; Channels; Circuits; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Error correction; Error correction & detection; Estimates; Fault tolerance; Learning; Mathematical and Computational Physics; Microprocessors; Molecular; Noise measurement; Optical and Plasma Physics; Physics; Physics and Astronomy; Probability distribution; Protocol; Quantum computers; Qubits (quantum computing); Theoretical
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/s41567-023-02042-2

Noise in quantum computers can result in biased estimates of physical observables. Accurate bias-free estimates can be obtained using probabilistic error cancellation, an error-mitigation technique that effectively inverts well-characterized noise channels. Learning correlated noise channels in large quantum circuits, however, has been a major challenge and has severely hampered experimental realizations. Our work presents a practical protocol for learning and inverting a sparse noise model that is able to capture correlated noise and scales to large quantum devices. These advances allow us to demonstrate probabilistic error cancellation on a superconducting quantum processor, thereby providing a way to measure noise-free observables at larger circuit volumes. Probabilistic error cancellation could improve the performance of quantum computers without the prohibitive overhead of fault-tolerant error correction. The method has now been demonstrated on a device with 20 qubits.