[2508.09844] On the Generalization Limits of Quantum Generative Adversarial Networks with Pure State Generators

Quantum Physics arXiv:2508.09844 (quant-ph) [Submitted on 13 Aug 2025 (v1), last revised 4 Mar 2026 (this version, v2)] Title:On the Generalization Limits of Quantum Generative Adversarial Networks with Pure State Generators Authors:Jasmin Frkatovic, Akash Malemath, Ivan Kankeu, Yannick Werner, Matthias Tschöpe, Vitor Fortes Rey, Sungho Suh, Paul Lukowicz, Nikolaos Palaiodimopoulos, Maximilian Kiefer-Emmanouilidis View a PDF of the paper titled On the Generalization Limits of Quantum Generative Adversarial Networks with Pure State Generators, by Jasmin Frkatovic and 9 other authors View PDF HTML (experimental) Abstract:We investigate the capabilities of Quantum Generative Adversarial Networks (QGANs) in image generations tasks. Our analysis centers on fully quantum implementations of both the generator and discriminator. Through extensive numerical testing of current main architectures, we find that QGANs struggle to generalize across datasets, converging on merely the average representation of the training data. When the output of the generator is a pure-state, we analytically derive a lower bound for the discriminator quality given by the fidelity between the pure-state output of the generator and the target data distribution, thereby providing a theoretical explanation for the limitations observed in current models. Our findings reveal fundamental challenges in the generalization capabilities of existing quantum generative models. While our analysis focuses on QGANs, th...