Quantum Programming

Anya Tafliovich, Eric C. R. Hehner

The subject of this work is quantum predicative programming -- the study of developing of programs intended for execution on a quantum computer. We look at programming in the context of formal methods of program development, or programming methodology. Our work is based on probabilistic predicative programming, a recent generalisation of the well-established predicative programming. It supports the style of program development in which each programming step is proven correct as it is made. We inherit the advantages of the theory, such as its generality, simple treatment of recursive programs, time and space complexity, and communication. Our theory of quantum programming provides tools to write both classical and quantum specifications, develop quantum programs that implement these specifications, and reason about their comparative time and space complexity all in the same framework.

Ellie D’Hondt

Djabeur Mohamed Seifeddine Zekrifa

Junjie Luo, Pengzhan Zhao, Zhongtao Miao +2 more

As quantum programming evolves, more and more quantum programming languages are being developed. As a result, debugging and testing quantum programs have become increasingly important. While bug fixing in classical programs has come a long way, there is a lack of research in quantum programs. To this end, this paper presents a comprehensive study on bug fixing in quantum programs. We collect and investigate 96 real-world bugs and their fixes from four popular quantum programming languages (Qiskit, Cirq, Q#, and ProjectQ). Our study shows that a high proportion of bugs in quantum programs are quantum-specific bugs (over 80%), which requires further research in the bug fixing domain. We also summarize and extend the bug patterns in quantum programs and subdivide the most critical part, math-related bugs, to make it more applicable to the study of quantum programs. Our findings summarize the characteristics of bugs in quantum programs and provide a basis for studying testing and debugging quantum programs.

Shaukat Ali, Tao Yue

Quantum programming languages provide necessary constructs to program quantum computers. To write such programs, one needs to understand the characteristics of quantum computers such as superposition and entanglement, which are novel as compared to programming with classical computers. Understanding these characteristics requires an understanding of quantum physics. Thus, there is a need to build high-level modeling abstractions of quantum programs for software engineers who are used to program on classical computers to understand and model quantum programs at a high-level of abstraction and independent of quantum platforms. To this end, we present some ideas for developing such quantum software modeling languages, by presenting a conceptual model of quantum programs and an example of modeling the state-based behavior of quantum entanglement program. Moreover, we present some open issues in the area of modeling quantum programs.

Jeff W. Sanders, Paolo Zuliani