When Abstraction Breaks Physics: Rethinking Modular Design in Quantum Software

TL;DR

This paper explores the fundamental conflicts between classical abstraction principles and quantum semantics, proposing new design principles and research directions for physically sound quantum software abstractions.

Contribution

It identifies how naive abstractions can violate quantum physics and introduces design principles and research directions for sound quantum software engineering.

Findings

Naive abstractions can violate quantum physical constraints.

Proposed design principles for quantum abstraction mechanisms.

Suggested research directions include quantum type systems and contract-based modules.

Abstract

Abstraction is a fundamental principle in classical software engineering, which enables modularity, reusability, and scalability. However, quantum programs adhere to fundamentally different semantics, such as unitarity, entanglement, the no-cloning theorem, and the destructive nature of measurement, which introduce challenges to the safe use of classical abstraction mechanisms. This paper identifies a fundamental conflict in quantum software engineering: abstraction practices that are syntactically valid may violate the physical constraints of quantum computation. We present three classes of failure cases where naive abstraction breaks quantum semantics and propose a set of design principles for physically sound abstraction mechanisms. We further propose research directions, including quantum-specific type systems, effect annotations, and contract-based module design. Our goal is to initiate a systematic rethinking of abstraction in quantum software engineering, based on quantum semantics and considering engineering scalability.