The quantum internet, which will be a hybrid of quantum and classical networks, is expected to provide information-theoretic security for data transmission. Classical networks have well-established protocols for reliable end-to-end transmission that use duplicating the classical bits implicitly. However, due to the no-cloning theorem, quantum bits (qubits) cannot be copied. In this paper, we propose to use a Universal Quantum Copying Machine (UQCM) to create imperfect clones and summarizes the Quantum Automatic Repeat Request (QARQ) protocol, which is inspired by its classical counterpart. To investigate the viability of QARQ, a simulation platform is created considering Nitrogen-vacancy (NV) center qubit platform that implements QARQ for quantum communication. The results explore the applications it is suitable for while maintaining enough quality of the qubit state. Two major quantum technologies are studied for these protocols: Direct Transmission (DT), and Teleportation (TP). It has been shown that for short distance communication DT provides better fidelity than TP while for long-distance communication TP outperforms DT and hence improves the QARQ performance as well.
The quantum internet, which will be a hybrid of quantum and classical networks, is expected to provide information-theoretic security for data transmission. Classical networks have well-established protocols for reliable end-to-end transmission that use duplicating the classical bits implicitly. However, due to the no-cloning theorem, quantum bits (qubits) cannot be copied. In this paper, we propose to use a Universal Quantum Copying Machine (UQCM) to create imperfect clones and summarizes the Quantum Automatic Repeat Request (QARQ) protocol, which is inspired by its classical counterpart. To investigate the viability of QARQ, a simulation platform is created considering Nitrogen-vacancy (NV) center qubit platform that implements QARQ for quantum communication. The results explore the applications it is suitable for while maintaining enough quality of the qubit state. Two major quantum technologies are studied for these protocols: Direct Transmission (DT), and Teleportation (TP). It has been shown that for short distance communication DT provides better fidelity than TP while for long-distance communication TP outperforms DT and hence improves the QARQ performance as well.
Quantum computing allows the implementation of powerful algorithms with enormous computing capabilities and promises a secure quantum Internet. Despite the advantages brought by quantum communication, certain communication paradigms are impossible or cannot be completely implemented due to the no-cloning theorem. Qubit retransmission for reliable communications and point-to-multipoint quantum communication (QP2MP) are among them. In this paper, we investigate whether a Universal Quantum Copying Machine (UQCM) generating imperfect copies of qubits can help. Specifically, we propose the Quantum Automatic Repeat Request (QARQ) protocol, which is based on its classical variant, as well as to perform QP2MP communication using imperfect clones. Note that the availability of these protocols might foster the development of new distributed quantum computing applications. As current quantum devices are noisy and they decohere qubits, we analyze these two protocols under the presence of various sources of noise. Three major quantum technologies are studied for these protocols: direct transmission (DT), teleportation (TP), and telecloning (TC). The Nitrogen-Vacancy (NV) center platform is used to create simulation models. Results show that TC outperforms TP and DT in terms of fidelity in both QARQ and QP2MP, although it is the most complex one in terms of quantum cost. A numerical study shows that the QARQ protocol significantly improves qubit recovery and that creating more clones does not always improve qubit recovery.
Quantum internet, which is expected to be a combination of quantum and classical networks, promises to provide information-theoretic security for data exchange. Classical networks have well-established protocols for reliable end-to-end transmission that implicitly make use of duplicating classical bits. However, quantum bits (qubits) cannot be copied due to the no-cloning theorem. In this paper, we take advantage of the principle of creating imperfect clones using a Universal Quantum Copying Machine (UQCM) and propose the Quantum Automatic Repeat Request (QARQ) protocol, inspired by its classical equivalent. A simulation platform has been developed to study the feasibility of QARQ. Results show that our proposal is well suited for applications that are compatible with low fidelity requirements.
This paper is a tutorial-style introduction to methods and protocols for reliable transmission of quantum information over noisy quantum links. The exposition is based on a design philosophy that parallels classical link-layer mechanisms such as forward error correction and Automatic Repeat reQuest (ARQ). It starts by drawing analogies and highlights differences between classical and quantum links. Such analogies are used as guiding principles, with explicit attention to where the classical correspondence no longer applies and where non-classical constraints and resources govern the protocol design. The emphasis is on the fact that classical reliability is achieved through fungible and cloneable bits, whereas unknown quantum states cannot be copied or freely retransmitted. In addition, quantum information is subject to stringent physical constraints due to decoherence as well as the need for transduction between stationary and flying qubits. Quantum error correction is presented as the analogue of classical forward error correction, where logical qubits are protected by encoding them into larger entangled code spaces and using syndrome measurements to infer and correct errors without collapsing the encoded state. It then introduces teleportation-based link abstractions, in which transmission of an unknown qubit is realized by consuming shared Bell pairs together with classical messages. Entanglement purification protocols play a role similar to ARQ-style reliability enhancement by converting many noisy entangled pairs into fewer, higher-fidelity pairs at the cost of additional resources. The paper is written from the perspective of classical communication engineering and is intended as a guide for translating the relevant ideas toward reliable quantum links and networks.
Most quantum communication tasks need to rely on the transmission of quantum signals over long distances. Unfortunately, transmission of such signals is most often limited by losses in the channel, the same issue that affects classical communication. Simple signal amplification provides an elegant solution for the classical world, but this is not possible in the quantum world, as the no-cloning theorem forbids such an operation and, thus, an alternative approach, a quantum repeater, is needed. Quantum repeaters enable one to create a known maximally entangled state between the end points of the network by first segmenting the network into pieces, creating entanglement between the segments, and then, connecting those entanglement to create the required long range entanglement. Quantum teleportation then allows an unknown quantum message to be transmitted between them using the long-range entangled state. This form of quantum communication will be at the heart of the future quantum Internet. In this review, we will detail various approaches to quantum repeaters, and discuss their expected performance and limitations.
Quantum networks play a pivotal role in quantum information science, which not only provide a secure communication platform for remote access to quantum computers but also serve as the strategic core for achieving large-scale quantum information processing, forming the foundational infrastructure for the future global-scale quantum internet. Quantum teleportation, which enables the transmission of unknown quantum states over long distances by employing quantum entanglement together with classical communication, is essential for the distribution of quantum resources in the construction of the global-scale quantum internet. To realize a global-scale quantum internet, quantum repeater protocols represent one of the most promising approaches for enabling quantum communication between any nodes. This concise review presents representative experimental demonstrations of quantum teleportation for constructing quantum networks across different physical platforms. Along this trajectory, the review discusses current challenges, open issues, and future perspectives toward scalable and practical quantum internet.
Quantum communication and information networks offer unprecedented processing efficiency and security for data transfers. Technologies like quantum key distribution (QKD), quantum repeaters, quantum memory, and quantum entanglement sources are enabling technologies that ensure secure communication. QKD methods use quantum physics concepts to establish cryptographic keys, while quantum repeaters compensate for signal loss in fiber optic cables. Quantum memory enables storage and retrieval of quantum information, while quantum entanglement generators generate entangled photon pairs. Artificial intelligence and machine learning have significantly improved the efficacy and security of quantum communication. These methods can facilitate ultra-secure, reliable, large-scale communication and even a future quantum internet by analyzing quantum protocols and mitigating noise-induced errors. QKD protocols ensure secure communication channels, while quantum repeaters establish secure long-distance communication lines by mitigating signal loss. Traditional Internet technology is susceptible to surveillance due to Shannon's information theory and mathematics. The quantum internet (QI) uses satellite-based quantum communication and quantum cryptographic protocols for physical QI. Quantum entanglement sources fortify secure communication protocols, improving resistance to attacks. Quantum information networks (QINs) enhance computing, sensing, and security capabilities over extended distances. The development of reliable, robust communication systems depends on these technologies. Quantum-secured networks enhance urban security, smart management, and infrastructure protection by providing data privacy and facilitating secure data transmission, thereby facilitating robust infrastructure and technological development.