Quantum-Enhanced Generative Models for Rare Event Prediction

TL;DR

This paper introduces a hybrid quantum-classical generative model designed to improve rare event prediction by better capturing tail distributions and increasing sample diversity, outperforming classical models in various datasets.

Contribution

The paper presents the Quantum-Enhanced Generative Model (QEGM), integrating quantum circuits with deep latent-variable models, introducing a tail-aware loss and quantum noise for improved rare event modeling.

Findings

QEGM reduces tail KL divergence by up to 50%.

QEGM improves rare-event recall and coverage calibration.

Outperforms classical models like GAN, VAE, and Diffusion in experiments.

Abstract

Rare events such as financial crashes, climate extremes, and biological anomalies are notoriously difficult to model due to their scarcity and heavy-tailed distributions. Classical deep generative models often struggle to capture these rare occurrences, either collapsing low-probability modes or producing poorly calibrated uncertainty estimates. In this work, we propose the Quantum-Enhanced Generative Model (QEGM), a hybrid classical-quantum framework that integrates deep latent-variable models with variational quantum circuits. The framework introduces two key innovations: (1) a hybrid loss function that jointly optimizes reconstruction fidelity and tail-aware likelihood, and (2) quantum randomness-driven noise injection to enhance sample diversity and mitigate mode collapse. Training proceeds via a hybrid loop where classical parameters are updated through backpropagation while quantum parameters are optimized using parameter-shift gradients. We evaluate QEGM on synthetic Gaussian mixtures and real-world datasets spanning finance, climate, and protein structure. Results demonstrate that QEGM reduces tail KL divergence by up to 50 percent compared to state-of-the-art baselines (GAN, VAE, Diffusion), while improving rare-event recall and coverage calibration. These findings highlight the potential of QEGM as a principled approach for rare-event prediction, offering robustness beyond what is achievable with purely classical methods.