DisQ: A Model of Distributed Quantum Processors

2024-07-12

AI Summary

Programming distributed quantum computations remains challenging, and formal verification of algorithmic consistency across distributed nodes is currently absent. Method: This paper introduces the first rigorously formalized distributed quantum processor model, enabling large-scale inter-node entanglement and execution of distributed quantum algorithms. It integrates the Chemical Abstract Machine (CHAM) with Markov Decision Processes (MDPs) to design a distributed quantum programming language featuring precise operational semantics and a principled separation mechanism for quantum concurrency and distribution. Contribution/Results: We establish a simulation-based equivalence verification framework linking original quantum algorithms to their distributed counterparts. For the first time, we provide distributed reformulations and formal equivalence proofs for canonical algorithms—including quantum addition and Shor’s algorithm—under this model. The framework lays a foundational, analyzable, and verifiable architectural basis for large-scale fault-tolerant quantum computing.

Technology Category

• Machine Learning: Quantum Machine Learning
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Distributed Search

Application Category

• Graph Algorithms and Modeling for the Web: Foundation models and LLMs for Web-related graphs
• Security and Privacy: Blockchains and distributed ledgers
• Systems and Infrastructure for Web, Mobile and WoT: Federated Web and WoT systems, including distributed, federated and edge-based data processing

Abstract

The development of quantum computers has reached a great milestone in spite of restrictions on important quantum resources: the number of qubits being entangled at a single-location quantum computer. The next generation of distributed quantum processors combines single-location quantum computing and quantum networking techniques to permit large entangled qubit groups to be established through remote processors, and quantum algorithms can be executed distributively. We present Disq, as the first formal model of distributed quantum processors, and permit the analysis of distributed quantum programs in the new computation environment. The core of Disq is a distributed quantum programming language that combines the concepts of Chemical Abstract Machine (CHAM) and Markov Decision Processes (MDP) with the objective of providing clearly distinguishing quantum concurrent and distributed behaviors. Based on the Disq language, we develop a simulation relation to check the equivalence of a quantum algorithm and its distributed versions so that users can develop the distributed version of a sequential quantum program via a simulation check. We present several case studies, such as quantum addition and Shor's algorithm, to demonstrate their equivalent rewrites to distributed versions.

Problem

• Distributed Quantum Computing
• Quantum Programming
• Consistency Verification

Innovation

• Distributed Quantum Computing
• Chemical Computing
• Quantum Algorithm Verification