A Quantum Neural Network Transfer-Learning Model for Forecasting Problems with Continuous and Discrete Variables

This study introduces a continuous-variable quantum neural network (CV-QNN) model designed as a transfer-learning approach for forecasting problems. The proposed quantum technique features a simple structure with only eight trainable parameters, a single quantum layer with two wires to create entanglement, and ten quantum gates, hence the name QNNet10, effectively mimicking the functionality of classical neural networks. A notable aspect is that the quantum network achieves high accuracy with random initialization after a single iteration. This pretrained model is innovative as it requires no training or parameter tuning when applied to new datasets, allowing for parameter freezing while enabling the addition of a final layer for fine-tuning. Additionally, an equivalent discrete-variable quantum neural network (DV-QNN) is presented, structured similarly to the CV model. However, analysis shows that the two-wire DV model does not significantly enhance performance. As a result, a four-wire DV model is proposed, achieving comparable results but requiring a larger and more complex structure with additional gates. The pretrained model is applied to five forecasting problems of varying sizes, demonstrating its effectiveness.