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Main Authors: Chaves, Rodrigo, Kumar, Kunal, Chagas, Bruno, Linerud, Rory, Sorem, Brannen, Mancilla, Javier, Bell, Bryn
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.06473
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author Chaves, Rodrigo
Kumar, Kunal
Chagas, Bruno
Linerud, Rory
Sorem, Brannen
Mancilla, Javier
Bell, Bryn
author_facet Chaves, Rodrigo
Kumar, Kunal
Chagas, Bruno
Linerud, Rory
Sorem, Brannen
Mancilla, Javier
Bell, Bryn
contents This paper investigates whether hybrid quantum-classical machine learning can deliver practical improvements in financial fraud detection performance for card-based and other payment transactions. Building on a Guided Quantum Compressor architecture, the approach integrates an autoencoder, a variational quantum circuit, and a classical neural head, and then embeds this hybrid model into a mixture-of-experts framework including a state-of-the-art gradient-boosted tree classifier. Using a European credit card dataset with severe class imbalance, the routed hybrid architecture with 0.6 threshold achieves average precision scores of $0.793\pm0.085$ compared to $0.770\pm0.096$ of XGBoost on 3 repeated 5-fold cross-validation benchmarks. Precision and recall comparisons reveals a possible trade-off of fraud and nominal detections with a reduction in false positives at the cost of a small reduction in fraud detections. The improvements are achieved while adding only 7 to 21 minutes of extra inference time depending on the choice of hyperparameters. These results indicate that selectively routing transactions to quantum-classical models can enhance fraud detection while remaining compatible with the latency and operational constraints of modern financial institutions.
format Preprint
id arxiv_https___arxiv_org_abs_2603_06473
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Mixture-of-Experts Framework for Practical Hybrid-Quantum Models in Credit Card Fraud Detection
Chaves, Rodrigo
Kumar, Kunal
Chagas, Bruno
Linerud, Rory
Sorem, Brannen
Mancilla, Javier
Bell, Bryn
Quantum Physics
This paper investigates whether hybrid quantum-classical machine learning can deliver practical improvements in financial fraud detection performance for card-based and other payment transactions. Building on a Guided Quantum Compressor architecture, the approach integrates an autoencoder, a variational quantum circuit, and a classical neural head, and then embeds this hybrid model into a mixture-of-experts framework including a state-of-the-art gradient-boosted tree classifier. Using a European credit card dataset with severe class imbalance, the routed hybrid architecture with 0.6 threshold achieves average precision scores of $0.793\pm0.085$ compared to $0.770\pm0.096$ of XGBoost on 3 repeated 5-fold cross-validation benchmarks. Precision and recall comparisons reveals a possible trade-off of fraud and nominal detections with a reduction in false positives at the cost of a small reduction in fraud detections. The improvements are achieved while adding only 7 to 21 minutes of extra inference time depending on the choice of hyperparameters. These results indicate that selectively routing transactions to quantum-classical models can enhance fraud detection while remaining compatible with the latency and operational constraints of modern financial institutions.
title A Mixture-of-Experts Framework for Practical Hybrid-Quantum Models in Credit Card Fraud Detection
topic Quantum Physics
url https://arxiv.org/abs/2603.06473