Quantum Data Networks (QDNs) are vital to building Distributed Quantum Computing (DQC) systems. Though several communication protocols have been proposed for QDNs, most of them are at the network layer or below. The only transport layer protocol [1] used batch processing of requests for End-to-End (E2E) quantum data transmission. It not only limits the quantum resource utilization, more importantly, it cannot guarantee reliable E2E quantum data transmission. In this paper, we propose the first asynchronous transportation layer protocol, called AQTP, for QDNs to achieve high-speed and reliable E2E quantum data transmission. AQTP has several distinct features: (i) each quantum node locally allocates quantum resources in order to improve scalability; (ii) requests are processed in an asynchronous manner, which results in a higher quantum resource utilization; and (iii) it ensures reliable data transmission even if the teleportation operations fail. Extensive simulations show that compared with a batch processed transport layer protocol, AQTP can increase the network throughput by up to 82.97%, and reduce the Average Task Completion Time (ATCT) of DQC tasks by up to 94.69%.
Quantum Data Networks (QDNs) are vital to building Distributed Quantum Computing (DQC) systems. Though several communication protocols have been proposed for QDNs, most of them are at the network layer or below. The only transport layer protocol [1] used batch processing of requests for End-to-End (E2E) quantum data transmission. It not only limits the quantum resource utilization, more importantly, it cannot guarantee reliable E2E quantum data transmission. In this paper, we propose the first asynchronous transportation layer protocol, called AQTP, for QDNs to achieve high-speed and reliable E2E quantum data transmission. AQTP has several distinct features: (i) each quantum node locally allocates quantum resources in order to improve scalability; (ii) requests are processed in an asynchronous manner, which results in a higher quantum resource utilization; and (iii) it ensures reliable data transmission even if the teleportation operations fail. Extensive simulations show that compared with a batch processed transport layer protocol, AQTP can increase the network throughput by up to 82.97%, and reduce the Average Task Completion Time (ATCT) of DQC tasks by up to 94.69%.
Quantum computing holds a great promise and this work proposes to use new quantum data networks (QDNs) to connect multiple small quantum computers to form a cluster. Such a QDN differs from existing QKD networks in that the former must deliver data qubits reliably within itself. Two types of QDNs are studied, one using teleportation and the other using tell-and-go (TAG) to exchange quantum data. Two corresponding quantum transport protocols (QTPs), named Tele-QTP and TAG-QTP, are proposed to address many unique design challenges involved in reliable delivery of data qubits, and constraints imposed by quantum physics laws such as the no-cloning theorem, and limited availability of quantum memory. The proposed Tele-QTP and TAG-QTP are the first transport layer protocols for QDNs, complementing other works on the network protocol stack. Tele-QTP and TAG-QTP have novel mechanisms to support congestion-free and reliable delivery of streams of data qubits by managing the limited quantum memory at end hosts as well as intermediate nodes. Both analysis and extensive simulations show that the proposed QTPs can achieve a high throughput and fairness. This study also offers new insights into potential tradeoffs involved in using the two methods, teleportation and TAG, in two types of QDNs.
Quantum computing holds great promise and this work proposes to use new quantum data networks (QDNs) to connect multiple small quantum computers to form a cluster. Such a QDN differs from existing quantum key distribution (QKD) networks in that the former must deliver data quantum bits (i.e., qubits) reliably between different quantum computers. Two families of QDNs are studied, one using teleportation, named Tele-QDN, and the other using tell-and-go (TAG), named TAG-QDN. In order to provide reliable delivery of data qubits, while addressing QDN-specific constraints imposed by quantum physics laws such as the no-cloning theorem, and limited availability of quantum memory, two corresponding transport layer protocols suitable for distributed implementation are designed and evaluated. Such distributed quantum transport protocols (DTPs), named Tele-DTP and TAG-DTP, are the first-of-its-kind and are complementary to existing works on the protocol stack for QDNs which are at the network layer and below. Both analysis and extensive simulations show that the proposed DTPs can achieve high throughput and fairness. This study also offers new insights into potential tradeoffs involved in using different types of QDNs.
Quantum Data Networks (QDNs) typically leverage teleportation to reliably send data quantum bits (called qubits) to their destinations. To teleport a data qubit from Alice to Bob, one entanglement connection between Alice and Bob needs to be established. Accordingly, we have to establish as many entanglement connections as possible with limited quantum resources in order to maximize the network throughput. Conventional methods assume a known traffic matrix and calculate the paths to establish entanglement connections in one batch using a centralized algorithm. However, these methods are not scalable in large scale QDNs since it is time consuming to optimize the entanglement paths for a batch of requests, which may result in a long time slot duration and significantly reduce the network throughput. To address this issue, we propose an Online Entanglement Routing (OER) scheme which determines the entanglement paths for each request when it arrives. In addition, OER pursues work conservation and fairness among all requests in the QDNs. Through extensive simulations, we demonstrate that OER not only outperforms two representative heuristics by up to 61.27% and 52.79%, respectively, in terms of average request completion time, but also achieves a better fairness performance than these two counterparts.
The quantum Internet relies on the ability to distribute entangled quantum bits (ebits) between quantum memories at the end nodes, to perform applications like blind or distributed quantum computing that are impossible if end nodes are connected via a classical, i.e., non-quantum network. This need creates new challenges due to the fragile nature of entanglement, which decoheres over short timescales and cannot be amplified, buffered, or retransmitted. Two broad categories of approaches have been proposed in the scientific literature to realize such an entanglement distribution in a given path: one relying on a synchronous time-slotted model, and another one where intermediate nodes interact asynchronously. However, both of them implicitly assume a serial operation, where one ebit is established and made available to the application on end nodes before creating a new one. This is inefficient in long-range networks, with high transmission latencies, if the intermediate nodes have multiple memory qubits that could be used in parallel. To overcome this limitation, in this paper, we study the implications of multiplexing concurrent ebit requests on the same quantum, for both synchronous and asynchronous operation. Furthermore, for the latter, we define a novel distribution protocol, called HOPPER, where the intermediate nodes make autonomous and hop-by-hop decisions on the use of their local resources when establishing an ebit. With numerical simulations, we show that HOPPER is effective in handling multiple ebit requests in parallel, and it exhibits significantly better performance than a synchronous alternative in different scenarios.
This paper presents a novel protocol for secure distributed data transmission leveraging the principles of quantum teleportation. The core claim of this protocol is to achieve secure data transmission utilizing quantum teleportation technology. The proposed mechanism relies on quantum entanglement to facilitate the instantaneous transfer of quantum states and incorporates classical communication for error correction, thereby ensuring both the security and reliability of the transmission process. The significance of this work lies in its potential to provide a higher level of security compared to traditional data transmission methods. The protocol details the necessary steps, including entanglement distribution, state transfer, and classical communication phases, with a focus on minimizing the impact of noise and maintaining the integrity of the transmitted information. This protocol offers a viable pathway for building quantum networks capable of secure data exchange, contributing to advancements in quantum cryptography and distributed quantum computing.
Remote entanglement distribution plays a crucial role in quantum networks, which can support many essential and exciting quantum applications. As the network scale expands, it is urgent to design a general and efficient remote entanglement distribution protocol. Nowadays, connection-oriented remote entanglement distribution protocols are available to achieve reliable entanglement distribution. However, in memory-limited quantum networks, connection-oriented entanglement distribution protocols cannot utilize entanglement resources fully and increase the delay of End-to-End (E2E) entanglement connection establishment. To overcome these shortcomings of existing entanglement distribution protocols, we design a connectionless remote entanglement distribution protocol to let Source-Destination (S-D) pairs compete for entanglement resources simultaneously. In our protocol, a fair request scheduling algorithm is proposed to reduce the waiting time without entanglement connections between S-D pairs. Furthermore, a fast scheduling trigger mechanism is proposed to perform entanglement swapping timely to reduce the delay of E2E entanglement connection establishment. The simulation results show that the designed protocol has advantages in terms of resource utilization, throughput, the service completion time of S-D pairs, and the maximum waiting time, compared with the existing remote entanglement distribution protocol.