A Multi‐Classification Hybrid Quantum Neural Network Using an All‐Qubit Multi‐Observable Measurement Strategy

Abstract

Quantum machine learning is a promising application of quantum computing for data classification. However, most of the previous research focused on binary classification, and there are few studies on multi‐classification. The major challenge comes from the limitations of near‐term quantum devices on the number of qubits and the size of quantum circuits. In this paper, we pro-pose a hybrid quantum neural network to implement multi‐classification of a real‐world dataset. We use an average pooling downsampling strategy to reduce the dimensionality of samples, and we design a ladder‐like parameterized quantum circuit to disentangle the input states. Besides this, we adopt an all‐qubit multi‐observable measurement strategy to capture sufficient hidden information from the quantum system. The experimental results show that our algorithm outperforms the classical neural network and performs especially well on different multi‐class datasets, which provides some enlightenment for the application of quantum computing to real‐world data on near-term quantum processors.