Developing and deploying advanced Quantum Repeater (QR) technologies will be necessary to scale quantum networks to longer distances. Depending on the error mitigation mechanisms adopted to suppress loss and errors, QRs are typically classified into memory-based or all-photonic QRs; and each type of QR may be best suited for a specific type of underlying quantum technology, a particular scale of quantum networks, or a specific regime of operational parameters. We perform theoretical analysis and simulations of quantum repeaters and networks to investigate the relative performance and resource requirements of different quantum network paradigms. Our results will help guide the optimization of quantum hardware and components and shed light on the role of a robust control plane. We present our research findings on theoretical analysis and simulations of memory-based first-generation trapped-ion quantum repeaters and networks, and all-photonic entanglement-based quantum repeaters and networks. We study the relative performance in terms of entanglement generation rate and fidelity, as well as the resource requirements of these two different quantum network paradigms.
Developing and deploying advanced Quantum Repeater (QR) technologies will be necessary to scale quantum networks to longer distances. Depending on the error mitigation mechanisms adopted to suppress loss and errors, QRs are typically classified into memory-based or all-photonic QRs; and each type of QR may be best suited for a specific type of underlying quantum technology, a particular scale of quantum networks, or a specific regime of operational parameters. We perform theoretical analysis and simulations of quantum repeaters and networks to investigate the relative performance and resource requirements of different quantum network paradigms. Our results will help guide the optimization of quantum hardware and components and shed light on the role of a robust control plane. We present our research findings on theoretical analysis and simulations of memory-based first-generation trapped-ion quantum repeaters and networks, and all-photonic entanglement-based quantum repeaters and networks. We study the relative performance in terms of entanglement generation rate and fidelity, as well as the resource requirements of these two different quantum network paradigms.
Developing and deploying advanced Quantum Repeater (QR) technologies will be necessary to scale quantum networks at longer distances. Depending on the error mitigation mechanisms adopted to suppress loss and errors, QRs are typically classified into “memory-based” or “all-photonic” QRs, and each type of QR may be best suited for a specific type of underlying quantum technology, a particular scale of quantum network, or a specific regime of operational parameters. Modeling and simulation of quantum repeaters and networks can help in understanding the relative performance and resource requirements of different types of QRs, identify tradeoffs of alternative quantum network architectures, optimize quantum hardware, and assist in the design of a robust control plane. This paper introduces a quantum repeater simulation toolkit based on NetSquid, which includes component models and protocols to study advanced quantum repeater networks. We present our initial research findings on modeling and simulation of “allphotonic” entanglement-based QRs and “memory-based” first generation trapped ion QRs. We study the relative performance and resource requirements of these two different types of QRs and networks. The performance metrics include entanglement generation rate and fidelity between the endpoints of the network. For fair comparison of resource requirements of different types of QRs, entanglement generation rate is normalized by the total number of matter qubits involved.
Abstract Scaling quantum networks to long distances necessitates the development of advanced quantum repeater (QR) technologies. Depending on the error mitigation mechanisms adopted to suppress loss and errors, QRs are typically classified into memory-based or all-photonic QRs; and each type of QR may be best suited for a specific type of underlying quantum technology, a particular scale of quantum networks, or a specific regime of operational parameters. This paper presents a comparative theoretical and simulation-based analysis of first-generation memory-based trapped-ion QRs and networks, and all-photonic entanglement-based QRs and networks. Our model incorporates a wide range of realistic parameters and noise sources to evaluate performance trade-offs. Major research findings of this study include: (a) the entanglement rate does not necessarily scale with the number of QRs. Although adding repeaters in a chain helps to reduce photon loss in quantum links, it also introduces overheads that can be attributed to imperfect photon collection, inefficient quantum frequency conversion, and limited detector efficiency. The entanglement rate only improves when the distance between QRs exceeds a certain threshold, specifically, when the reduction in photon loss in quantum links gained by adding QRs outweighs the inherent overheads they introduce. (b) Without quantum error correction and entanglement purification, the entanglement fidelity decreases with the number of QRs, regardless of the chain distance. Finally, the theoretical models and simulation software package developed in this study provide a versatile framework for the design and evaluation of future QR technologies, protocols, and architectures.
This paper explores the design and implementation of trapped-ion quantum repeaters and networks using modeling and simulation. We aim to quantitatively understand the practical architecture design and resource requirements of trapped-ion entanglement-based quantum repeater paradigms. Our simulation results explore entanglement rate and fidelity as key performance metrics, and we discuss the major challenges for practical deployment of quantum networks and future directions for research and development in order to meet these challenges.
In this thesis, I explore whether it is possible to build a unified Quantum Internet architecture that supports different types of quantum repeaters -- especially the two most distinct and seemingly incompatible ones: memory-based quantum repeaters and all-photonic, memoryless repeaters. These technologies have traditionally been developed with the aim of becoming the single dominant solution, but I ask: Can they work together in the same network? What kind of architecture would support both? And how can simulation help us understand what is needed to manage such a network at scale? To address these questions, I propose an architecture based on an existing recursive network design and programmable RuleSet-based protocols that can coordinate diverse hardware components. I introduce a new emitter-photon building block to bridge memory-based and all-photonic segments, and show how classical networking abstractions can be extended to manage quantum operations. While I have developed a simulation tool grounded in these architectural principles and validated it against existing simulators and analytical models, a full-scale investigation of the resource trade-offs and performance implications remains future work. Nevertheless, the results so far suggest that a unified, heterogeneous quantum network is not only possible but increasingly practical with current technologies -- though ongoing experimental progress will be essential to fully realize this vision.
Purpose of the study: systematization and critical analysis of existing approaches to error suppression in quantum repeaters, as well as to assess their advantages and limitations for the implementation of scalable quantum networks and the quantum internet. Methods of research: the paper provides a detailed analysis of modern literature, including a comparison of various quantum repeater schemes, as well as an assessment of resource costs and performance. Result(s): quantum repeaters can be divided into three generations, each of which demonstrates optimal efficiency under certain conditions. The first generation, implementing probabilistic error suppression by generating heralded entanglement and two-way entanglement distillation, is easy to implement and provides the basic functionality of a quantum network, but requires significant time due to the need to exchange classical signals and long-term storage of quantum states. The second generation combines probabilistic entanglement generation with deterministic operation error suppression using quantum error correction, which reduces the requirements for long-term quantum memory, although the exchange of classical signals between neighboring nodes remains mandatory. The third generation relies entirely on deterministic error suppression using one-way classical communication, which allows for a significant reduction in time delays and high entanglement generation rates, despite the need for a denser arrangement of repeaters and high-quality local gates. In addition, the review covers new areas such as memoryless repeaters and all-photonic repeaters. The conducted comparative analysis of resource costs demonstrates that optimization of repeater operating parameters is a key factor for the implementation of scalable quantum networks, which is of direct importance for quantum key distribution, quantum metrology, and distributed quantum computing. Scientific novelty: the scientific novelty lies in the integration of disparate approaches to the implementation of quantum repeaters into a single holistic representation, which allows for an objective assessment of their efficiency by key parameters. The review highlights the potential for new classes of repeaters, such as memoryless repeaters and all-photonic circuits, to become important elements in the development of a quantum internet.
Emerging experimental quantum network deployments are based on collaborations between research institutions and rely on telecommunications fiber infrastructure. Currently, such networks consist of mostly Dual Input Repeaters (DIRs) and can be viewed as composed of (mostly) line graphs. In order to evaluate the performance of such networks (e.g., in terms of Entangled Pair Rate, EPR, and average Fidelity) we developed a custom quantum network simulation platform that takes into account both the quantum and classical network components. To support the verification of the simulation results, we develop a novel approach for performance analysis of DIRs. We compare the simulation results to the analytical results for DIRs and to prior results for repeaters with more than two inputs. We observe that although the expected memory utilization cannot be bounded, \emph{a small DIR memory size is sufficient and leads to minimal performance degradation}. For line networks with a single repeater and 3 repeaters, we explore the dependency of incoming and outgoing memory size requirements on the number of nodes (network size), their connectivity (fiber length) and various quantum error settings (amplitude damping and phase flip channels). We evaluate the \emph{EPR} and the \emph{average Fidelity} for a sub-network of a deployed network with 3 repeaters, using two alternative paths. We show that as the number of nodes increases or when the fiber lengths between nodes differ significantly, additional node memory is needed to maintain the same EPR (qubits are stored for longer duration to allow completion of entanglement across the network). We also show that the memory size should be above some minimum threshold to allow EP creation (EPR >0) as pair selection and swapping completion propagate across the network.