Automated equivalence checking of concurrent quantum systems

Ardeshir-Larijani, E., Gay, S. J. and Nagarajan, R. (2018) Automated equivalence checking of concurrent quantum systems. ACM Transactions on Computational Logic, 19(4), 28. (doi: 10.1145/3231597)

Abstract

The novel field of quantum computation and quantum information has gathered significant momentum in the last few years. It has the potential to radically impact the future of information technology and influence the development of modern society. The construction of practical, general purpose quantum computers has been challenging, but quantum cryptographic and communication devices have been available in the commercial marketplace for several years. Quantum networks have been built in various cities around the world and a dedicated satellite has been launched by China to provide secure quantum communication. Such new technologies demand rigorous analysis and verification before they can be trusted in safety- and security-critical applications. Experience with classical hardware and software systems has shown the difficulty of achieving robust and reliable implementations. We present CCSq, a concurrent language for describing quantum systems, and develop verification techniques for checking equivalence between CCSq processes. CCSq has well-defined operational and superoperator semantics for protocols that are functional, in the sense of computing a deterministic input-output relation for all interleavings arising from concurrency in the system. We have implemented QEC (Quantum Equivalence Checker), a tool that takes the specification and implementation of quantum protocols, described in CCSq, and automatically checks their equivalence. QEC is the first fully automatic equivalence checking tool for concurrent quantum systems. For efficiency purposes, we restrict ourselves to Clifford operators in the stabilizer formalism, but we are able to verify protocols over all input states. We have specified and verified a collection of interesting and practical quantum protocols, ranging from quantum communication and quantum cryptography to quantum error correction.

• Item Type: Articles
• Additional Information: The first author is supported in part by a grant from the School of Computer Science, Institute for Research in Fundamental Sciences (IPM), Iran. The third author is partially supported by EU ICT COST Action IC1405 “Reversible Computation—Extending Horizons of Computing".
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gay, Professor Simon
• Authors: Ardeshir-Larijani, E., Gay, S. J., and Nagarajan, R.
• College/School: College of Science and Engineering > School of Computing Science
• Journal Name: ACM Transactions on Computational Logic
• Publisher: Association for Computing Machinery
• ISSN: 1529-3785
• ISSN (Online): 1557-945X
• Published Online: 20 November 2018
• Copyright Holders: Copyright © 2018 Association for Computing Machinery
• First Published: First published in ACM Transactions on Computational Logic 19(4):28
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher