Qmod: Expressive High-Level Quantum Modeling

2025-02-26

AI Summary

Current quantum programming relies predominantly on low-level gate-level circuit descriptions, resulting in obscured algorithmic intent, poor readability, and limited code reusability. To address these limitations, this paper introduces Qmod—a high-level, intent-oriented quantum programming language. Qmod features a novel quantum numeric variable and expression system that natively supports diverse encoding paradigms, including digital, phase, and amplitude representations, and incorporates resource-aware fixed-point arithmetic. By decoupling high-level algorithmic semantics from low-level circuit implementations, Qmod enables abstraction-driven development; an automated compilation framework bridges the gap between abstract specifications and hardware-executable circuits. Compared to existing quantum languages, Qmod significantly enhances algorithm readability, developer productivity, and software maintainability. It establishes a new paradigm for quantum algorithm engineering—one that balances expressive power with practical deployability.

Technology Category

• Machine Learning: Quantum Machine Learning
• Knowledge Representation and Reasoning: Qualitative Reasoning
• Computer Vision: Multi-modal Vision

Application Category

• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Graph Algorithms and Modeling for the Web: Querying, indexing, and retrieval in Web-related graphs
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions

Abstract

Quantum computing hardware is advancing at a rapid pace, yet the lack of high-level programming abstractions remains a serious bottleneck in the development of new applications. Widely used frameworks still rely on gate-level circuit descriptions, causing the algorithm's functional intent to become lost in low-level implementation details, and hindering flexibility and reuse. While various high-level quantum programming languages have emerged in recent years - offering a significant step toward higher abstraction - many still lack support for classical-like expression syntax, and native constructs for useful quantum algorithmic idioms. This paper presents Qmod, a high-level quantum programming language designed to capture algorithmic intent in natural terms while delegating implementation decisions to automation. Qmod introduces quantum numeric variables and expressions, including digital fixed-point arithmetic tuned for compact representations and optimal resource usage. Beyond digital encoding, Qmod also supports non-digital expression modes - phase and amplitude encoding - frequently exploited by quantum algorithms to achieve computational advantages. We describe the language's constructs, demonstrate practical usage examples, and outline future work on evaluating Qmod across a broader set of use cases.

Problem

• Develop high-level quantum programming abstractions
• Enhance quantum algorithm expression and flexibility
• Support diverse quantum encoding and resource optimization

Innovation

• High-level quantum programming language
• Quantum numeric variables and expressions
• Support for non-digital expression modes