Automatic De-Quantization of Quantum Programs Using Constant Propagation

2026-05-21

AI Summary

This work addresses the pressing challenge of high error rates and costly resource demands on near-term quantum devices by proposing the first hybrid constant propagation model that integrates quantum and classical state tracking. By performing cross-domain analysis, the method automatically identifies quantum gates that can be replaced with classical computations and implements a dequantization optimization within the MQT Core compiler framework. This approach significantly reduces the number of multi-qubit gates, thereby enhancing both execution efficiency and robustness of quantum programs on noisy hardware across standard benchmark circuits.

Abstract

Quantum computing promises to solve problems beyond the reach of classical computers, but today's quantum hardware is error-prone and much slower than classical hardware. Every quantum operation is costly, making it crucial to minimize quantum resource usage in near-term algorithms. Quantum resources should only be used when they are truly essential for quantum advantage, and not wasted on operations that can be efficiently handled by classical computation. In this work, we focus on de-quantizing quantum operations to classical computation whenever possible. The approach we propose for this is hybrid quantum-classical constant propagation, an optimization which reduces quantum operations by trading them for fast, reliable classical instructions. This is done by tracking between quantum and classical states to identify and eliminate unnecessary quantum gates and controls. We formalize a hybrid state model for quantum-classical constant propagation, implement our optimizations in the open-source MQT Core tool, and evaluate them on benchmark circuits. The obtained results show that quantum-classical constant propagation can reduce costly multi-qubit operations, making quantum programs more practical and robust for near-term devices. This opens the door to new hybrid compiler strategies that leverage the best of both quantum and classical worlds.

Problem

• de-quantization
• quantum resource minimization
• hybrid quantum-classical computation
• quantum circuit optimization

Innovation

• de-quantization
• constant propagation
• hybrid quantum-classical compilation
• quantum circuit optimization
• NISQ