Abstract
Variational quantum algorithms are often limited by barren plateaus: gradients vanish as circuit size and depth increase, making quantum neural networks difficult to train. We propose Q-Capsule, a localized capsule-based quantum neural architecture that mitigates this problem through register partitioning, local readout, sparse inter-capsule coupling, trainable data re-uploading, and Quantum Fisher Information Matrix (QFIM)-guided adaptive depth growth. By restricting the dominant support of each observable to a small capsule and controlling inter-capsule entanglement, Q-Capsule preserves useful gradient signals while retaining communication between local quantum representations. As the register width increases, Q-Capsule consistently maintains stable gradient variance, whereas globally entangling baselines exhibit exponential suppression with a log-gradient-variance slope near -ln 2 per qubit. Q-Capsule also produces more structured optimization landscapes, higher parameter efficiency, improved robustness to depolarizing noise, and lower measurement requirements. Its adaptive policy achieves 98.1% accuracy on binary classification and 97.7% on four-class classification, while using approximately 73% fewer two-qubit gates than the fixed-deep model on the multiclass task.
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Cite this article
APA 7
Fime, A. A., Samiha, T. Z., Zaman, S., Pados, D., Sklivanitis, G., Shahid, A. R., & Imteaj, A. (2026). Q-Capsule: A Localized Capsule-Based Quantum Neural Architecture for Barren Plateau Mitigation. https://omanscience.com/en/articles/q-capsule-a-localized-capsule-based-quantum-neural-architecture-for-barren-plateau-mitigation
MLA 9
Fime, Awal Ahmed, et al. "Q-Capsule: A Localized Capsule-Based Quantum Neural Architecture for Barren Plateau Mitigation." https://omanscience.com/en/articles/q-capsule-a-localized-capsule-based-quantum-neural-architecture-for-barren-plateau-mitigation.
Chicago (author–date)
Fime, Awal Ahmed, Tasfia Zaman Samiha, Saika Zaman, Dimitris Pados, George Sklivanitis, Abdur R. Shahid, and Ahmed Imteaj. 2026. "Q-Capsule: A Localized Capsule-Based Quantum Neural Architecture for Barren Plateau Mitigation." https://omanscience.com/en/articles/q-capsule-a-localized-capsule-based-quantum-neural-architecture-for-barren-plateau-mitigation.
Harvard
Fime, A. A., Samiha, T. Z., Zaman, S., Pados, D., Sklivanitis, G., Shahid, A. R. and Imteaj, A. (2026) 'Q-Capsule: A Localized Capsule-Based Quantum Neural Architecture for Barren Plateau Mitigation', Available at: https://omanscience.com/en/articles/q-capsule-a-localized-capsule-based-quantum-neural-architecture-for-barren-plateau-mitigation.
Vancouver
Fime AA, Samiha TZ, Zaman S, Pados D, Sklivanitis G, Shahid AR, et al. Q-Capsule: A Localized Capsule-Based Quantum Neural Architecture for Barren Plateau Mitigation. https://omanscience.com/en/articles/q-capsule-a-localized-capsule-based-quantum-neural-architecture-for-barren-plateau-mitigation
IEEE
A. A. Fime, T. Z. Samiha, S. Zaman, D. Pados, G. Sklivanitis, A. R. Shahid, and A. Imteaj, "Q-Capsule: A Localized Capsule-Based Quantum Neural Architecture for Barren Plateau Mitigation," https://omanscience.com/en/articles/q-capsule-a-localized-capsule-based-quantum-neural-architecture-for-barren-plateau-mitigation.