Noise-Resilient Hybrid Quantum Neural Network Framework: Enabling Reliable Quantum Machine Learning in the NISQ Era

This paper introduces a systematic noise-resilient Hybrid Quantum Neural Network (HQNN) framework. Through innovative techniques like stability regularization, multi-observable quantum feature extraction, and learnable classical readout, it achieves an accuracy of 96% in a simulated NISQ noise environment, providing a feasible solution for the practical deployment of quantum machine learning. The framework focuses on the completeness of the hybrid process, including noise injection, feature extraction, classical readout interpretation, etc., significantly enhancing model robustness.

Current quantum computers are in the NISQ era, with sufficient qubits but high noise, leading to a sharp drop in the performance of quantum machine learning models on real hardware. Traditional HQNNs use fixed parity check thresholds for classical readout, compressing rich quantum measurement information and causing loss of useful data. Core research insight: HQNN performance depends on a complete hybrid process (noise injection, feature extraction, readout interpretation, entanglement architecture selection, robustness verification).

The framework has four key innovations:

1. Learnable Classical Readout Mechanism: Takes circuit measurement distribution as quantum features input to the learnable readout layer, increasing noise accuracy from 36.67% to 82.22%;
2. Multi-Observable Feature Extraction: Constructs a 31-dimensional feature vector (bitstring probability distribution, single-qubit Z expectation, pairwise ZZ correlation, etc.) to provide rich information for classical models;
3. Stability Regularization Training: Combines clean/noise behavior and perturbation stability; the optimal configuration achieves both clean and noise accuracy of 96% under depolarizing noise without performance loss;
4. Architecture Search Optimization: Linear entanglement combined with random forest readout performs best, with clean/noise accuracy of 89.33% and 88.67% respectively.

Multi-Channel Noise Test (eval_noise=0.05):

• Depolarizing noise: clean 96% / noise 94.67%, accuracy drop of 0.0133;
• Bit flip: clean 94.67% / noise 94.67%, no drop;
• Phase flip: clean 95.33% / noise 95.33%, no drop;
• Amplitude damping: clean 96% / noise 92.67%, drop of 0.0333. Noise Scan Experiment: Linear HQNN maintains an accuracy of 84.67% when noise level ≤0.05, with a significant drop only when >0.07.

The framework is built on a mature toolchain:

• Quantum computing SDKs: Qiskit, Cirq;
• Simulators and ML libraries: Qiskit Aer, Qiskit Machine Learning, PennyLane;
• Classical ML and numerical tools: scikit-learn, NumPy, Matplotlib. On top of these libraries, the framework builds reusable layers for evaluation, optimization, reporting, and robustness analysis.

The project includes 13 demo experiments covering three frameworks: Qiskit, Cirq, and PennyLane: Core Demos: HQNN toy classifier, VQE energy minimization, QAOA MaxCut, noise-resilient HQNN, etc.; Industry-Inspired Demos: Medical risk classification, energy grid optimization, cybersecurity anomaly detection, HQNN interpretability, etc.

This research provides a complete path from simple HQNN benchmarks to reusable methodologies, helping to discover noise-resilient hybrid quantum-classical learning configurations. It offers practitioners standardized dataset processing, noise analysis toolkits, robustness metrics, and a complete benchmark pipeline. As quantum hardware evolves, this systematic noise robustness research will become a key bridge for quantum machine learning to move from the lab to applications.