Quantum communications using entangled photons as qubits offer a promising approach to quantum key distribution, enhancing network security. However, establishing successful entanglement links between distant nodes is challenging due to factors like distance and rapid entanglement decay, resulting in low network transmission efficiency for quantum key distribution. This paper studies the problem of finding the maximum quantum communication network transmission scheme for multiple source-destination pairs with considering the success rate of quantum entangle establishments. We propose the Feasible Quantum Communication Network Transmission (fQUIET) algorithm, which leverages network transformation and auxiliary network construction. The Maximum Quantum commUnIcation nEtwork Transmission (mQUIET) algorithm is further proposed by iteratively searching for augmenting paths. Through theoretical analysis, we demonstrate that the mQUIET algorithm is capable of achieving the maximum QCN transmission scheme. Extensive experiments are carried out and the results reveal that our suggested algorithms have superior performance compared to existing methods.
Quantum communications using entangled photons as qubits offer a promising approach to quantum key distribution, enhancing network security. However, establishing successful entanglement links between distant nodes is challenging due to factors like distance and rapid entanglement decay, resulting in low network transmission efficiency for quantum key distribution. This paper studies the problem of finding the maximum quantum communication network transmission scheme for multiple source-destination pairs with considering the success rate of quantum entangle establishments. We propose the Feasible Quantum Communication Network Transmission (fQUIET) algorithm, which leverages network transformation and auxiliary network construction. The Maximum Quantum commUnIcation nEtwork Transmission (mQUIET) algorithm is further proposed by iteratively searching for augmenting paths. Through theoretical analysis, we demonstrate that the mQUIET algorithm is capable of achieving the maximum QCN transmission scheme. Extensive experiments are carried out and the results reveal that our suggested algorithms have superior performance compared to existing methods.
Quantum networks are an actively researched and promising field, aiming to achieve efficient quantum information transmission by interconnecting quantum nodes. In large-scale quantum networks, end-to-end throughput is a critical factor that affects the overall performance of the network. The maximum flow problem, extensively studied in classical network theory, identifies a set of paths between the source and destination nodes that maximizes the total flow. This study extends the maximum flow problem to quantum networks, focusing on coordinating multiple paths for multi-path quantum communication. We propose a Quantum Multi-Path Communication Protocol (QMCP) that employs maximum flow theory to allocate transmission resources across multiple nodes efficiently, thus maximizing the total transmission capacity from the source to the destination. Our evaluation demonstrates that QMCP significantly enhances end-to-end throughput in quantum networks.
The unbreakable security and higher data rates offered by quantum communication networks have made quantum communication an inevitable necessity of the future. Many quantum communication frameworks, such as quantum key distribution and super dense coding, require entangled pairs to be shared between the source and destination nodes. Communication nodes in quantum networks have a minimum fidelity requirement for the entangled pairs. If the fidelity requirement is not satisfied, the entangled pairs may not be used for the desired operations. Successful sharing of the entangled pairs between the nodes is a crucial step in making quantum communication practical. In this work, we propose a framework to maximize entanglement sharing between a source and multiple destination nodes in a fair manner. We consider a system that takes advantage of the purification process to improve the fidelity of the entangled pairs when necessary. The proposed solution framework provides the optimal number of entangled pairs required for the purification process and the optimal transmission rate at the source node to achieve the desired system objective. The non-convex problem is first transformed into a convex form, and then a Lagrangian dual-based framework is proposed to find the optimal solution values. Moreover, to optimize the number of entangled pairs for purification at each link, we derive a closed-form expression that provides the optimal value in a single step. Selected simulation results demonstrate that the proposed framework exhibits excellent performance.
Entanglement distribution over long distances is one of the main problems in the existing quantum communication networks. Most of the existing methods of establishing entanglement paired link (Einstein, Podolsky, Rosen - EPR pairs) between distant nodes assume symmetric network topologies comprised of links with identical EPR generation capacities. In this work, the entanglement rate capacity of randomly distributed quantum ad hoc networks is investigated. To this end, constant fidelity maximum flow (CFMF) of entanglement problem is defined, and its theoretical analysis is presented. A new heuristic algorithm, i.e., Entanglement Swapping Scheme Search (ESSS), is presented to find the best possible swapping scheme over a multi-hop entanglement path. Furthermore, Shortest Path Entanglement Flow (SPEF) algorithm is introduced as an effective heuristic solution for this problem. Analysis shows that there is a trade-off between the desired constant target fidelity and the entanglement generation rate (maximum flow) of the network.
This paper presents a novel approach to optimizing Grover’s algorithm for addressing the routing problem in quantum wireless communication networks. We begin by conducting a comprehensive analysis of key quantum communication technologies, including quantum teleportation and quantum entanglement swapping, and subsequently construct a quantum wireless communication network model grounded in these principles. Building on this foundation, we design and implement a multi-level quantum wireless network information transmission mechanism, incorporating quantum channels for identity authentication to ensure secure communication. Focusing on the routing challenges in quantum wireless communication networks, we propose innovative applications and optimizations of Grover’s quantum search algorithm. Specifically, we introduce an improved algorithm that efficiently searches for routing paths with maximal metrics within a limited number of hops. This enhancement not only significantly increases routing efficiency but also mitigates the risk of quantum channel disconnection caused by the depletion of entangled quantum pairs, thereby improving the overall success rate of communication. Simulation and experimental results demonstrate that the proposed optimization algorithm substantially enhances the routing performance of quantum wireless communication networks while maintaining robust security measures. This study offers a new solution to the routing challenges in quantum wireless communication networks and significantly optimizes Grover’s algorithm, contributing to the development of more efficient and reliable quantum communication networks.
Quantum computing holds the promise of solving problems difficult for classical computers. However, we are still in the era of Noisy Intermediate-Scale Quantum (NISQ) computers, necessary to establish effective distributed quantum communication protocols to distribute complex quantum computing tasks across different quantum computers for execution. Significant progress has been made in quantum communication technology, particularly in quantum path creation and resource scheduling. The establishment of quantum paths relies on quantum entanglement and quantum relay technologies, achieving long-distance, high-fidelity quantum state transmission through entanglement swapping between multiple relays. However, resources in quantum communication networks are limited and expensive, making efficient resource scheduling strategies crucial for improving overall network efficiency. To address these issues, we design a network protocol that includes the Historical Weighted Fidelity Routing (HWFR) algorithm and the Dynamic Multi-Priority Quantum Scheduling (DMPQS) algorithm to enhance communication reliability across quantum computers. Both algorithms aim to enhance the reliability of quantum links, optimize resource utilization, and adapt to dynamic changes in the links. The former algorithm dynamically selects the optimal path by considering factors such as link length, noise level, entanglement success rate, and quantum relay resource constraints, ensuring high-fidelity and reliable quantum communication. The latter dynamically adjusts request priorities based on the urgency of quantum service requests and fidelity requirements, optimizing resource utilization. Experimental results show that the proposed protocol performs excellently in terms of an average response time of requests and link utilization, effectively improving the utilization efficiency of network resources and the overall performance of the system.
Quantum entanglement enables important computing applications such as quantum key distribution. Based on quantum entanglement, quantum networks are built to provide long-distance secret sharing between two remote communication parties. Establishing a multi-hop quantum entanglement exhibits a high failure rate, and existing quantum networks rely on trusted repeater nodes to transmit quantum bits. However, when the scale of a quantum network increases, it requires end-to-end multi-hop quantum entanglements in order to deliver secret bits without letting the repeaters know the secret bits. This work focuses on the entanglement routing problem, whose objective is to build long-distance entanglements via untrusted repeaters for concurrent source-destination pairs through multiple hops. Different from existing work that analyzes the traditional routing techniques on special network topologies, we present a comprehensive entanglement routing model that reflects the differences between quantum networks and classical networks as well as a new entanglement routing algorithm that utilizes the unique properties of quantum networks. Evaluation results show that the proposed algorithm Q-CAST increases the number of successful long-distance entanglements by a big margin compared to other methods. The model and simulator developed by this work may encourage more network researchers to study the entanglement routing problem.