Quantum Error Mitigation via Noise Correlation Stretch Factors

The patent segments the error correction problem into two distinct parts: (1) quantum error mitigation techniques applied to near-term hardware with limited qubits, and (2) classical post-processing algorithms that analyze measurement data to extract accurate expectation values. This segmentation allows near-term quantum computers to perform useful computations without requiring full fault-tolerant quantum error correction architectures.

The patent introduces classical computing as an intermediary between the noisy quantum hardware and the final accurate results. Classical algorithms process the measurement data from quantum circuits, applying error mitigation techniques to recover accurate expectation values without requiring the quantum hardware itself to be fault-tolerant. This intermediary approach bridges the gap between noisy near-term devices and accurate computational results.

The patent employs periodic measurement and reset cycles in quantum Monte Carlo simulations. Instead of requiring long continuous quantum evolution, the system performs repeated short-duration quantum circuit executions with periodic resetting of qubits to their initial states. This periodic action allows accumulation of statistical data over time without suffering from prolonged decoherence, as each quantum circuit execution remains within the coherence time window.

The patent maintains continuous progress toward accurate results through repeated quantum circuit executions and classical post-processing. Rather than requiring a single long quantum evolution that would suffer from decoherence, the system continuously accumulates measurement data from multiple short executions, using classical algorithms to progressively refine expectation value estimates. This continuous action approach achieves high precision without extending individual quantum circuit durations beyond coherence limits.