Understanding Software Defined Quantum Networks

⚛️ Quantum Networking Fundamentals: From Physical Protocols to Network Engineering 📜 The realization of the Quantum Internet promises transformative capabilities in unconditionally secure communication, distributed quantum computing, and high-precision quantum metrology. However, transitioning from isolated laboratory experiments to a scalable, multi-tenant network utility introduces deep orchestration challenges. Current development is largely siloed within the physics and optics communities, prioritizing hardware fidelities and photon sources, while theclassical networking community lacks the architectural models required to dynamically manage these fragile quantum resources. This tutorial bridges this disciplinary divide by providing a comprehensive, network-centric view of quantum networking. We systematically dismantle the idealized assumptions prevalent in current network simulators to directly address the “simulation–reality gap,” and we recast them as explicit control-plane constraints. To bridge this gap, we establish Software-Defined Quantum Networking (SDQN) not merely as an evolutionary management tool, but as a mandatory prerequisite for scale, and we prioritize the orchestration of a symbiotic, dual-plane architecture in which classical control dictates quantum data flow. Specifically, we synthesize reference models for SDQN and the Quantum Network Operating System (QNOS) for hardware abstraction, and we adapt a Quantum Network Utility Maximization (Q-NUM) framework as a unifying mathematical lens to help network engineers reason about the inherent trade-offs between entanglement routing, scheduling, and fidelity targets. Furthermore, we analyze Distributed Quantum AI (DQAI) over imperfect networks as a case study, illustrating how physical constraints such as probabilistic stragglers and decoherence fundamentally dictate application-layer viability. Ultimately, this tutorial equips network engineers with the operational mindset and architectural tools required to transition quantum networking from a bespoke physics experiment into a programmable, multi-tenant global infrastructure. ℹ️ A. Gkelias et al - EEE Department, Imperial College, London, UK -2026

🚀 Excited to share our latest quantum research published on arXiv! 🔬 Our paper, “OSI Stack Redesign for Quantum Networks: Requirements, Technologies, Challenges, and Future Directions,” tackles the pressing need to reimagine network architecture in the quantum era. 🧠 Classical OSI models were never built to handle the unique properties of quantum communication, such as entanglement, coherence fragility, and the no-cloning theorem. In this work, we propose a Quantum-Converged OSI stack, introducing new layers and reengineering existing ones to support teleportation, quantum security, and semantic orchestration powered by LLMs and QML. 📚 We reviewed and classified over 150+ key research contributions (IEEE, ACM, arXiv, MDPI, Web of Science) and organized them by layer, enabling technology (e.g., QKD, PQC, RIS), and use case—from satellite QKD to quantum IoT. 🧪 We also present: A taxonomy of hybrid control and trust mechanisms A simulation toolkit review (NetSquid, QuNetSim, QuISP) An evaluation framework built around fidelity, entropy, and latency Applications in healthcare telemetry, vehicular networks, and more 📡 This paper lays the groundwork for a programmable, AI-driven quantum networking model suitable for 7G and beyond. 🔗 Read the full paper: arxiv.org/abs/2506.12195 🙏 Grateful to co-authors Muhammad Kamran Saeed and Prof. Ashfaq Khokhar for their brilliant insights and collaboration. #QuantumComputing #QuantumNetworks #7G #Networking #AI #LLM #QuantumSecurity #Research #arXiv

Who says connectivity is only about chip design? One of the most striking insights I took away from my chat with Pedram Roushan (Google) a few weeks ago was about 𝗿𝗲𝘄𝗶𝗿𝗶𝗻𝗴 𝘁𝗵𝗲 𝗾𝘂𝗮𝗻𝘁𝘂𝗺 𝗴𝗿𝗶𝗱—𝗻𝗼𝘁 𝗶𝗻 𝗵𝗮𝗿𝗱𝘄𝗮𝗿𝗲, 𝗯𝘂𝘁 𝗶𝗻 𝗰𝗹𝗮𝘀𝘀𝗶𝗰𝗮𝗹 𝗰𝗼𝗻𝘁𝗿𝗼𝗹 𝗹𝗼𝗴𝗶𝗰. In superconducting systems, qubits sit on a 2D grid. Long-range couplers between distant qubits? Technically possible—but costly, complex, and challenging to scale. But here’s the twist: 𝗬𝗼𝘂 𝗱𝗼𝗻’𝘁 𝗮𝗹𝘄𝗮𝘆𝘀 𝗻𝗲𝗲𝗱 𝗵𝗮𝗿𝗱𝘄𝗮𝗿𝗲-𝗹𝗲𝘃𝗲𝗹 𝗰𝗼𝗻𝗻𝗲𝗰𝘁𝗶𝗼𝗻𝘀 𝗶𝗳 𝘆𝗼𝘂𝗿 𝗰𝗼𝗻𝘁𝗿𝗼𝗹 𝗲𝗹𝗲𝗰𝘁𝗿𝗼𝗻𝗶𝗰𝘀 𝗮𝗿𝗲 𝗳𝗮𝘀𝘁 𝗲𝗻𝗼𝘂𝗴𝗵. Measure one qubit → process that information immediately in classical hardware→ apply a conditional gate on another qubit anywhere on the chip. Suddenly, 𝘁𝗵𝗲 𝗴𝗿𝗶𝗱 𝗯𝗲𝗰𝗼𝗺𝗲𝘀 𝗳𝗹𝗲𝘅𝗶𝗯𝗹𝗲. Connectivity becomes programmable. “If your feedback loop takes 500 nanoseconds, the whole procedure becomes pointless. But if you can do it fast—really fast—you effectively stitch your sample together for logical operation.” This is where modern control systems (like Quantum Machines OPX series) come in—offering ultra-low latency feedforward and feedback that makes these strategies practical. It’s not just a clever trick for entanglement generation. It’s a paradigm shift: • Adaptive calibration during job execution • Fast conditional logic without reconfiguring the chip • Software-defined connectivity at scale    This feels like one of the most underrated, yet powerful, enablers for near-term quantum experiments. 📸 Image adapted from Google Quantum AI

The quantum internet has been impossible for a brutal reason. Last week, I watched a $15 million quantum computer wait 10 milliseconds to talk to another $15 million quantum computer sitting 10 meters away. Ten. Milliseconds. That's 200× longer than the computation itself took. This is why Google, IBM, and every quantum company builds monolithic processors instead of networked ones. The "entanglement rate gap" makes distributed quantum computing economically insane. Until now. We discovered something wild: trapped ions can multiplex across 250,000 parallel channels. Time bins. Wavelengths. Spatial modes. But every lab was using them one at a time, like having a 1000-lane highway and driving in a single lane. Our hierarchical multiplexing architecture coordinates these resources using algorithms borrowed from how AI agents share bandwidth. Result: 847× faster quantum networking. Same hardware. The math is violent: this drops the cost per entangled qubit from $10,000 to $12. What this unlocks: - Quantum computers that scale like AWS, not like the Large Hadron Collider - City-wide quantum networks by 2028 - Distributed quantum encryption that governments can't break Oxford proved that distributed quantum computing works in February. We just made it practical. African researchers are in this race. We have to be, because quantum networks will rewire global finance, cryptography, and AI infrastructure within a decade. Paper link below. The implementation roadmap costs $400K and takes 3 years. That's accessible. The question isn't whether quantum networks will happen. It's who builds them first. 🔗 Full technical paper: https://lnkd.in/ekVh6U8y #QuantumComputing #QuantumNetworks #EmergingTech #AfricaInnovation #QuantumInternet

[COMST Survey] A Survey of Quantum Internet Protocols from a Layered Perspective With the development of quantum technologies, the quantum internet has demonstrated unique applications beyond the classical internet and has been investigated extensively in recent years. In the construction of conventional internet software, the protocol stack is the core architecture for coordinating modules. Designing a protocol stack for the quantum internet is a challenging problem. In this context, the paper titled “A Survey of Quantum Internet Protocols from a Layered Perspective” by Yuan Li, Hao Zhang, Chen Zhang, Tao Huang, and F. Richard Yu systematically reviews the latest developments in quantum internet protocols from the perspective of protocol stack layering. By summarizing and analyzing the progress in each layer's protocols, the current research status and connections among the layers are revealed. The paper provides readers with a comprehensive understanding of the quantum internet and can help support researchers focusing on a single layer to define better the functions the layer should possess and optimize related protocols. By shifting focus from a single layer to a holistic view of the protocols across all layers of quantum networks, new challenges and opportunities for optimization previously overlooked are revealed.

QNodeOS, the first operating system designed specifically for quantum networks, represents a major step toward practical distributed quantum computing. Developed by members of the Quantum Internet Alliance (QIA)—including TU Delft, QuTech, University of Innsbruck, INRIA, and CNRS—this new system aims to standardize and simplify quantum network development, much like classical operating systems did for traditional computing. Unlike quantum computers, which perform calculations using quantum bits (qubits) with properties like superposition and entanglement, quantum networks are designed to connect these computers, enabling secure communication, distributed computing, and advanced quantum protocols. Until now, quantum network software has been hardware-specific and fragmented, limiting the scalability of quantum applications. QNodeOS solves this by introducing a hardware-agnostic, platform-independent framework, allowing developers to create quantum applications without needing deep knowledge of the underlying hardware. The operating system’s key functions include managing quantum information flow, synchronizing entanglement across multiple nodes, and coordinating devices in a quantum network. By abstracting away low-level quantum operations, QNodeOS provides a high-level programming environment, making it easier to develop, test, and deploy quantum network applications. This breakthrough lays the groundwork for the future of distributed quantum computing, where quantum devices can work together over vast distances. As quantum internet technology advances, QNodeOS could play a critical role in enabling applications such as ultra-secure quantum communication, cloud-based quantum computing, and advanced quantum sensing networks. With this development, the vision of a fully functional quantum internet is moving closer to reality.

At its core the team at Qunnect is focused on something fundamental: making entanglement a usable and distributed resource. We do not view quantum networks solely through the lens of security, because that does not capture what they truly enable. Our goal is to unlock applications that arise from generating, distributing, and maintaining versatile entangled states across distance in a controlled and reliable way. Once entanglement becomes a network resource, a new class of applications emerges. Distributed quantum computing is a clear example. Instead of pushing a single processor to its limits, smaller systems can be linked through shared entanglement. The network becomes the computer as scaling is no longer constrained to a single device. Networked quantum sensing is another. When sensors are entangled, their measurements are fundamentally correlated, enabling applications or levels of precision inaccessible to classical approaches. Timing, navigation, and geophysical monitoring all change when measurements are no longer independent and siloed. Classical and quantum networks must be evaluated differently. Classical networks move data efficiently. Quantum networks distribute quantum states. Once two locations are entangled, information can be teleported between them. These are fundamentally different functions. The usefulness of a quantum network is therefore tied to the correlations it can establish and maintain, and the capabilities those correlations unlock. A strong example of the power and originality of quantum correlations can be found here (The Quantum Insider): https://lnkd.in/esAYka3V What stands out is not communication in the traditional sense, but coordination enabled by shared entanglement. Separate systems can generate correlations that cannot be reproduced classically, even without exchanging information during the protocol. This reshapes how we think about distributed systems and decision-making. At Qunnect, we are actively working with design partners to showcase these types of usecases because they capture something essential. Even in the near term, there are scenarios where distributing entanglement changes what is possible. This is why we are proud to be the first company to deliver a turnkey quantum entanglement distribution system focused on applications beyond just cryptography, enabling our customers and partners to develop use cases today. This is the direction we have been building toward Qunnect: not a faster network and not only a more secure one, but infrastructure that makes quantum states available across distance in real operating environments. As we see every day, once that layer exists, the range of applications expands immediately. The question is no longer whether quantum networks are useful, but what new systems can be built on top of them and what they can enable that classical networks cannot.

🔴 #QUANTUM #INTERNET #OS 🔶️ Scientists have developed the world's first #operating #system (OS) designed for #quantum #computers, which could let them interconnect, thereby paving the way for a quantum internet. 🔶️ An OS, such as Microsoft Windows or Apple iOS, is the program responsible for managing every other application on a computer. However, most quantum computers are designed and built for a specific function; e.g., to run an experiment or simulation. 🔶️ This limits their potential functionality and hampers their connectivity. There are also different types of quantum computers that use different kinds of quantum bits (qubits) to achieve quantum superposition in different ways. 🔶️ But scientists have published a new study describing #QNodeOS, an OS for quantum computers that works with all kinds of machines irrespective of the type of qubits they use. 🔶️ #QNodeOS operates by combining a classical network processing unit (#CNPU), which is the logical element for initiating the execution of the code, with a quantum network processing unit (#QNPU), which controls the quantum code. Together, the CNPU and QNPU form the #QNodeOS, which controls a separate quantum device, called the #QDevice. 🔶️ The QDevice is quantum hardware-dependent technology responsible for executing quantum operations (#gates, #measurements and #entanglements). There would need to be a QDevice for every quantum computer that the QNodeOS is required to operate. 🔶️ A key component of the QNodeOS is the #QDriver, which connects the QNodeOS to the QDevice. The QDriver is the only part of the QNodeOS that is quantum hardware-dependent. It translates the platform-independent quantum operations from QNodeOS into platform-dependent instructions and vice versa, thus enabling the QNodeOS to control different types of quantum computers. 🔶️ Executing a process also requires  #NetQASM — a universal, platform-independent instruction set architecture for quantum internet applications. 🔶️ Further experimentation with the QNodeOS is required, like using more quantum computers of different types, as well as increasing the distance between them. 🔶️ The study highlighted that the architecture could be improved by having the CNPU and QNPU on a single system board, to avoid millisecond delays in their communication, rather than relying on two separate boards. 🔶️ An OS for quantum computers represents a major step forward in their development. One of the potential applications for a quantum computer OS is for distributed quantum computing, as well as potentially laying the foundations for a quantum internet. (Source Link in Comment) #innovation #technology #future #trends

Under the streets of Manhattan and Brooklyn. Through 60 Hudson, one of the most connected carrier hotels in the world. Real quantum entanglement at scale on 17.6 km of standard telecom fiber. With swapping rates 3+ orders of magnitude beyond prior efforts and fidelity above 99%. This is the full quantum networking stack coming together — hardware, protocol, control, orchestration. Most importantly, we ran this without the shared laser crutch that makes lab experiments unscalable by design. This real-world demo used fully independent quantum sources at each endpoint. With Cisco's quantum software stack handling timing coordination at picosecond precision across three geographically separated nodes using the White Rabbit protocol. Qunnect's room-temperature hardware at the edges. And cryogenic equipment only at the hub for efficiency. Any new nodes could be added to this network without touching the sync infrastructure. And with clean control and data plane separation.   Applying design patterns that scaled the classical internet to quantum networking. I wrote about what this milestone means and how it leads us one step closer to our vision of a quantum data center network, on the Cisco blog today. 🔗 Link in comments. 📸 Photo of Manhattan from the Brooklyn end, by me.

DARPA’s QuANET researchers have demonstrated the first functioning quantum-augmented network. Less than a year ago DARPA launched a new program called QuANET (Quantum-Augmented Network) to answer: Can we combine the best of classical and quantum communications to create a vastly more secure, resilient network? QuANET’s mission is to integrate quantum links into today’s internet infrastructure. The goal is to marry the unique “covertness” (stealth) of quantum communications with the ubiquity and scale of classical networks . And QuANET researchers just demonstrated a functioning quantum-augmented network. They encoded and sent images as quantum data on a beam of “squeezed” light. The initial attempt took five minutes, but after real-time optimization the team slashed it to just 0.7 milliseconds (~6.8 Mbps) – fast enough to stream HD video. This rapid improvement, achieved only ~10 months into the project, shows how quickly quantum networking is moving from lab theory toward practical reality. From a cybersecurity standpoint, QuANET could be impactful. Even the most advanced classical networks today remain vulnerable to relentless cyberattacks, whereas quantum communication can inherently bolster resilience – any eavesdropping or tampering attempt would disturb the quantum data and be detected. By embedding quantum encryption and transmissions into network architectures, QuANET aims to make critical infrastructure much harder to compromise. I find QuANET’s emergence to be a significant milestone. For years, quantum networking (even quantum-augmented networking) have been a niche research topic – often confined to laboratory demos or isolated testbeds. Now we’re seeing a major R&D agency actively bridging quantum and classical networks, which is a big leap toward mainstream adoption. It’s not every day you hear about an ASCII-art cat being beamed over a quantum link. More importantly, it shows that quantum-secure communication is becoming a reality. #Quantum #QuantumNetworking #PQC https://lnkd.in/gEhszfaC