Quantum Graph Attention Network: A Novel Quantum Multi-Head Attention Mechanism for Graph Learning

TL;DR

The paper introduces QGAT, a quantum-enhanced graph neural network that uses a single quantum circuit for multi-head attention, reducing complexity and improving learning of complex dependencies.

Contribution

It presents a novel quantum multi-head attention mechanism that shares parameters across heads using a single quantum circuit, enhancing efficiency and scalability.

Findings

QGAT effectively captures complex structural dependencies.

Quantum embedding improves robustness against noise.

QGAT integrates seamlessly with classical models.

Abstract

We propose the Quantum Graph Attention Network (QGAT), a hybrid graph neural network that integrates variational quantum circuits into the attention mechanism. At its core, QGAT employs strongly entangling quantum circuits with amplitude-encoded node features to enable expressive nonlinear interactions. Distinct from classical multi-head attention that separately computes each head, QGAT leverages a single quantum circuit to simultaneously generate multiple attention coefficients. This quantum parallelism facilitates parameter sharing across heads, substantially reducing computational overhead and model complexity. Classical projection weights and quantum circuit parameters are optimized jointly in an end-to-end manner, ensuring flexible adaptation to learning tasks. Empirical results demonstrate QGAT's effectiveness in capturing complex structural dependencies and improved generalization in inductive scenarios, highlighting its potential for scalable quantum-enhanced learning across domains such as chemistry, biology, and network analysis. Furthermore, experiments confirm that quantum embedding enhances robustness against feature and structural noise, suggesting advantages in handling real-world noisy data. The modularity of QGAT also ensures straightforward integration into existing architectures, allowing it to easily augment classical attention-based models.