OQTOPUS: Open Quantum Toolchain for OPerators and USers

Here are the slides for my presentation at FOSDEM2026.

Details of the event can be found at:
https://fosdem.org/2026/schedule/event/9UBLWQ-oqtopus/

Transcript

1. OQTOPUS: Building an Open-Source Full-Stack Quantum Cloud Infrastructure Feb. 1 FOSDEM 2026 Naoyuki Masumoto, Kousuke Miyaji, Satoyuki Tsukano The University of Osaka
2. About QIQB • I am Specially Appointed Researcher at QIQB, The University of Osaka, Japan. • Center for Quantum Information and Quantum Biology at The University of Osaka. • The center, as an international research hub for quantum innovations, promotes international academic exchanges and takes a key role in human resources development to social implementation. • Own and operate real quantum hardware with a full-stack software cloud service. • https://qiqb.osaka-u.ac.jp/en/about-qiqb Naoyuki Masumoto@UOsaka 2 Feb. 01 2026 https://qiqb.osaka-u.ac.jp/newstopics/pr20250414
3. From Theory to Reality: A Brief History(Theory) • The Birth: Quantum Mechanics(1925) • Heisenberg, Schrödinger, Dirac, etc.: Formulated the mathematical foundation. • The physical laws that describe the microscopic scale. • The Proposal: Simulating Nature • Richard Feynman (1981): Proposed using quantum systems to simulate quantum physics. • David Deutsch (1985): Defined the Universal Quantum Computer (Quantum Turing Machine). Naoyuki Masumoto@UOsaka 3 Feb. 01 2026 https://en.wikipedia.org/wiki/Paul_Dirac https://en.wikipedia.org/wiki/Richard_Feynman https://en.wikipedia.org/wiki/David_Deutsch
4. From Theory to Reality: A Brief History(Reality) Naoyuki Masumoto@UOsaka 4 Feb. 01 2026 https://www.itpro.com/technology/big-data/ibm-is-targeting-quantum-advantage-in-12-months-and-says-useful-quantum-computing-is-just-a-few-years-away •1999: The First Superconducting (Yasunobu Nakamura) •Achieved the world's first superconducting qubit at NEC. •~2014: The Engineering Breakthrough (John Martinis) •Martinis's team achieved high-fidelity quantum gates below the error correction threshold. •Turning point from "physics experiments" to scalable "computer engineering." •2016: The Dawn of Cloud Quantum Computing (IBM) •IBM put the first quantum processorQubit on the cloud, making hardware accessible globally.
5. What is Quantum Computer?(The Qubit) Feb. 01 2026 Naoyuki Masumoto@UOsaka 5 The New Unit of Information • Superposition: Unlike a bit (0 or 1), a qubit exists as a complex combination of both states simultaneously. • Entanglement: Deep correlation between qubits; the state of one instantly influences the other, regardless of distance.
6. What is Quantum Computer?(The Space) Feb. 01 2026 Naoyuki Masumoto@UOsaka 6 The Infinite Mathematical Playground •Hilbert Space: N qubits live in a complex vector space of 2! dimensions. •The Scale: With just 300 qubits, the state space is larger than the number of atoms in the observable universe. •Parallelism via Interference: Manipulating the entire probability space at once to "cancel" wrong answers and "amplify" the right one theoretically! The Harsh Reality (Practice) •Fragile & Noisy: Real-world qubits have low fidelity and are extremely sensitive to environmental noise. •Does Not Work as Predicted: Unlike ideal theory, errors accumulate instantly, causing the quantum state to collapse.
7. The Quantum Advantage • Targeting Combinatorial Complexity • Quantum Chemistry: Simulating nitrogen fixation for fertilizer or new battery materials. • Global Optimization: Solving logistics and supply chain problems at a massive scale. • Security: Factoring large primes (Shorʼs Algorithm) Naoyuki Masumoto@UOsaka 7 Feb. 01 2026 https://en.wikipedia.org/wiki/Peter_Shor
8. Implementation: Building the Quantum Machine Naoyuki Masumoto@UOsaka 8 Feb. 01 2026 •Any Microscopic System Works •Theoretically, any system following quantum mechanics can be a qubit. •We can use atoms, ions, photons, or artificial atoms which . •The "Golden Chandelier": The Dilution Refrigerator •We actually own and operate this hardware at QIQB, Osaka University. •The "Vacuum Tube Era" of Quantum •Today's quantum hardware is like the bulky, fragile vacuum tubes of early classical computer https://en.wikipedia.org/wiki/Colossus_computer https://www.osaka-u.ac.jp/ja/event/2023/11/10578
9. The Challenge of Closed Systems Naoyuki Masumoto@UOsaka 9 Feb. 01 2026 •The Current Landscape: Dominated by Closed Ecosystems. •Examples: IBM Quantum and Google Quantum AI offer powerful, but proprietary, cloud platforms. •The Issue with "Walled Gardens": •Vendor Lock-in: Users are tied to a single company's full stack, from SDK to hardware. •Limited Transparency: Researchers cannot fully see how their circuits are compiled or optimized. •No Standard "OS": There is no common, open infrastructure for operators to build their own quantum cloud.
10. Introducing OQTOPUS • Open Quantum Toolchain for Operators and Users. • Goal: Democratizing the quantum stack. • Joint Effort: Osaka University, Fujitsu, RIKEN, SEC, and TIS. • https://oqtopus-team.github.io/ Naoyuki Masumoto@UOsaka 10 Feb. 01 2026
11. High-Level Architecture (3-Layer Stack) • Frontend Layer: User interface and logic. • Cloud Layer: Scaling and orchestration. • Backend Layer: Hardware translation and control. Naoyuki Masumoto@UOsaka 11 Feb. 01 2026
12. Layer 1: Frontend Web UI & SDK for quantum circuit design. • Support for OpenQASM 3.0. • A language for quantum circuit. Naoyuki Masumoto@UOsaka 12 Feb. 01 2026
13. Layer 2: Cloud Naoyuki Masumoto@UOsaka 13 Feb. 01 2026 • Receive quantum jobs • OQTOPUS Cloud is responsible for job and user managements. • Web UI • An intuitive, browser-based dashboard. • Job monitoring: Real-time tracking of status.
14. Layer 3: Backend Layer • OQTOPUS Engine: Transpiling abstract circuits •Circuit Optimization: Rewriting generic circuits to match the specific topology of the superconducting chip. •Instruction Mapping: Translating OpenQASM 3.0 into hardware-executable operations. Naoyuki Masumoto@UOsaka 14 Feb. 01 2026
15. Milestones Naoyuki Masumoto@UOsaka 15 Feb. 01 2026 •Launch of Japanʼs first domestic 64-qubit superconducting quantum computer at RIKEN. •Expansion to Osaka University (QIQB) & AIST( National Institute of Advanced Industrial Science and Technology, Japan) •A turning point for open national quantum infrastructure. •OQTOPUS at the Core: Providing the unified software cloud layer for these flagship machines. RIKEN(Sep. 2023) UOsaka (Dec. 2023)
16. Why OSS Matters for Quantum Naoyuki Masumoto@UOsaka 16 Feb. 01 2026 •Interoperability: Avoiding vendor lock-in and ensuring long-term sustainability. •LPI Community Recognition: •Featured in the Linux Professional Institute (LPI) blog: "Open Source Communities Tackle Unique Challenges" (Aug 2025). •Recognized as a leading example of building a robust, international quantum OSS community. •https://www.lpi.org/blog/2025/08/07/quantum-computing-challenges- open-source-communities-part-1/ •Community: OSS developers can help build the next "Linux for Quantum."
17. Conclusion • The Future of Quantum Must be Open • Tested at QIQB & RIKEN: OQTOPUS is already powering national research infrastructure and real superconducting hardware. • Try the Playground Now: https://demo.oqtopus.io/ (interactive circuit composer & simulator) • Ready for Everyone: You don't need a dilution refrigerator to start; you can deploy OQTOPUS with simulators today. • Join the Community: We are building the "Linux for Quantum," and we need your expertise in cloud, compilers, and physics. Naoyuki Masumoto@UOsaka 17 Feb. 01 2026 https://github.com/oqtopus-team https://arxiv.org/abs/2507.23165 (*) * N. Kakuko et al., "A Practical Open-Source Software Stack for a Cloud-Based Quantum Computing System," 2025 IEEE International Conference on Quantum Computing and Engineering (QCE), Albuquerque, NM, USA, 2025, pp. 797-803, doi: 10.1109/QCE65121.2025.00092. https://demo.oqtopus.io/