🤖 AI Summary
This work establishes a formal axiomatic foundation for quantum programming, addressing core semantic challenges—including quantum conditionals, loops, tail recursion, and deferred measurement. Methodologically, it systematically extends classical Hoare logic to the quantum setting: it formalizes quantum if/while rules, introduces a tail-recursive quantum implementation mechanism, and proves a normal-form theorem relating quantum circuits to finite quantum programs—all fully mechanized in Coq. Key contributions are: (1) a characterization of algebraic properties of quantum programs and correctness-preserving program transformations; (2) a rigorous derivation of the deferred measurement principle; and (3) an identification of fundamental distinctions between quantum and classical program logics. The results provide a trustworthy theoretical framework and formal toolset for quantum compiler optimization and reliability verification of quantum code.
📝 Abstract
In this paper, we investigate the fundamental laws of quantum programming. We extend a comprehensive set of Hoare et al.'s basic laws of classical programming to the quantum setting. These laws characterise the algebraic properties of quantum programs, such as the distributivity of sequential composition over (quantum) if-statements and the unfolding of nested (quantum) if-statements. At the same time, we clarify some subtle differences between certain laws of classical programming and their quantum counterparts. Additionally, we derive a fixpoint characterization of quantum while-loops and a loop-based realisation of tail recursion in quantum programming. Furthermore, we establish two normal form theorems: one for quantum circuits and one for finite quantum programs. The theory in which these laws are established is formalised in the Coq proof assistant, and all of these laws are mechanically verified. As an application case of our laws, we present a formal derivation of the principle of deferred measurements in dynamic quantum circuits. We expect that these laws can be utilized in correctness-preserving transformation, compilation, and automatic code optimization in quantum programming. In particular, because these laws are formally verified in Coq, they can be confidently applied in quantum program development.