🤖 AI Summary
This work addresses one-class classification in high-dimensional, complex data by proposing NQSVDD, a classical-quantum hybrid framework that, for the first time, integrates trainable quantum data encoding and variational quantum circuits into this task. The method employs end-to-end optimization to jointly learn hierarchical representations from both classical neural networks and quantum modules, constructing a minimum-volume hyperspherical decision boundary in a compact latent space. Experimental results demonstrate that NQSVDD achieves or surpasses the AUC performance of classical Deep SVDD and existing quantum baselines across multiple benchmark datasets, while exhibiting high parameter efficiency and strong robustness to realistic noise.
📝 Abstract
One-class classification (OCC) is a fundamental problem in machine learning with numerous applications, such as anomaly detection and quality control. With the increasing complexity and dimensionality of modern datasets, there is a growing demand for advanced OCC techniques with better expressivity and efficiency. We introduce Neural Quantum Support Vector Data Description (NQSVDD), a classical-quantum hybrid framework for OCC that performs end-to-end optimized hierarchical representation learning. NQSVDD integrates a classical neural network with trainable quantum data encoding and a variational quantum circuit, enabling the model to learn nonlinear feature transformations tailored to the OCC objective. The hybrid architecture maps input data into an intermediate high-dimensional feature space and subsequently projects it into a compact latent space defined through quantum measurements. Importantly, both the feature embedding and the latent representation are jointly optimized such that normal data form a compact cluster, for which a minimum-volume enclosing hypersphere provides an effective decision boundary. Experimental evaluations on benchmark datasets demonstrate that NQSVDD achieves competitive or superior AUC performance compared to classical Deep SVDD and quantum baselines, while maintaining parameter efficiency and robustness under realistic noise conditions.