J un 2 01 1 Entangled Network and Quantum Communication (original) (raw)
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Effect of the Spin-Orbit Interaction (Heisenberg XYZ Model) on Partial Entangled Quantum Network
Journal of Quantum Information Science, 2014
Dzyaloshiniskii-Moriya (DM) interaction in three directions (D x , D y and D z ) is used to generate entangled network from partially entangled states in the presence of the spin-orbit coupling. The effect of the spin coupling on the entanglement between any two nodes of the network is investigated. The entanglement is quantified using Woottores concurrence method. It is shown that the entanglement decays as the coupling increases. For larger values of the spin coupling, the entanglement oscillates within finite bounds. For the initially entangled channels, the upper bound does not exceed its initial value, whereas the entanglement reaches its maximum value for the channels generated via indirect interaction.
Dynamics of the entanglement over noisy quantum networks
2014 International Conference on Computer and Information Sciences (ICCOINS), 2014
In this paper, the effect of homogeneous and nonhomogeneous magnetic fields as an external noisy on the entanglement dynamics over partial entangled state quantum network is studied. The Dzyaloshiniskii-Moriya (DM) interaction is used to generate entangled network from partially entangled states in the presence of the spin-orbit coupling. The entanglement between any two nodes is quantified using Wootter concurrence. The effect of homogeneous and non-homogeneous magnetic field in presence and absence of the spin coupling on the entanglement between any two nodes of the network is investigated. The results show that the homogeneous magnetic field has no effect on the entanglement without the presence of the spin-orbit interaction. The non-homogeneous magnetic field has a strong impact on the entanglement either with or without spin-orbit couplings. For initially entangled channels, the upper bound does not exceed its initial value, whereas for the channels generated via indirect interaction, the entanglement reaches its maximum value.
Communication via an entangled coherent quantum network
Physica Scripta, 2011
A quantum network is constructed via maximum entangled coherent states. The possibility of using this network to achieve communication between multi-participants is investigated. We showed that the probability of teleported unknown state successfully, depends on the size the used network. As the numbers of participants increases, the successful probability does not depend on the intensity of the field. The problem of implementing quantum teleportation protocol via a noise quantum network is discussed. We show one can send information perfectly with small values of the field intensity and larger values of the noise strength. The successful probability of this suggested protocol increases abruptly for larger values of the noise strength and gradually for small values. We show that for small size of the used quantum network, the fidelity of the teleported state decreases smoothly, while it decreases abruptly for larger size of network.
IEEE Communications Surveys & Tutorials
Over the past few decades, significant progress has been made in quantum information technology, from theoretical studies to experimental demonstrations. Revolutionary quantum applications are now in the limelight, showcasing the advantages of quantum information technology and becoming a research hotspot in academia and industry. To enable quantum applications to have a more profound impact and wider application, the interconnection of multiple quantum nodes through quantum channels becomes essential. Building an entanglement-assisted quantum network, capable of realizing quantum information transmission between these quantum nodes, is the primary goal. However, entanglement-assisted quantum networks are governed by the unique laws of quantum mechanics, such as the superposition principle, the no-cloning theorem, and quantum entanglement, setting them apart from classical networks. Consequently, fundamental efforts are required to establish entanglement-assisted quantum networks. While some insightful surveys have paved the way for entanglement-assisted quantum networks, most of these studies focus on enabling technologies and quantum applications, neglecting critical network issues. In response, this paper presents a comprehensive survey of entanglementassisted quantum networks. Alongside reviewing fundamental mechanics and enabling technologies, the paper provides a detailed overview of the network structure, working principles, and development stages, highlighting the differences from classical networks. Additionally, the challenges of building widearea entanglement-assisted quantum networks are addressed. Furthermore, the paper emphasizes open research directions, including architecture design, entanglement-based network issues, and standardization, to facilitate the implementation of future entanglement-assisted quantum networks.
All our former experience with application of quantum theory seems to say: what is predicted by quantum formalism must occur in laboratory. But the essence of quantum formalism -entanglement, recognized by Einstein, Podolsky, Rosen and Schrödinger -waited over 70 years to enter to laboratories as a new resource as real as energy. This holistic property of compound quantum systems, which involves nonclassical correlations between subsystems, is a potential for many quantum processes, including "canonical" ones: quantum cryptography, quantum teleportation and dense coding. However, it appeared that this new resource is very complex and difficult to detect. Being usually fragile to environment, it is robust against conceptual and mathematical tools, the task of which is to decipher its rich structure. This article reviews basic aspects of entanglement including its characterization, detection, distillation and quantifying. In particular, the authors discuss various manifestations of entanglement via Bell inequalities, entropic inequalities, entanglement witnesses, quantum cryptography and point out some interrelations. They also discuss a basic role of entanglement in quantum communication within distant labs paradigm and stress some peculiarities such as irreversibility of entanglement manipulations including its extremal form -bound entanglement phenomenon. A basic role of entanglement witnesses in detection of entanglement is emphasized. quantum computing with quantum data structure 37 IX. Classical algorithms detecting entanglement 37 X. Quantum entanglement and geometry 38 XI. The paradigm of local operations and classical communication (LOCC) 39 A. Quantum channel -the main notion 39 B. LOCC operations 39 XII. Distillation and bound entanglement 41 A. One-way hashing distillation protocol 41 B. Two-way recurrence distillation protocol 42 93 C. Byzantine agreement -useful entanglement for quantum and classical distributed computation 94 ACKNOWLEDGMENTS 94
Entanglement Evolution of Noisy Teleportation
2018
We generalize the teleportation protocol of Bennet et al. to a noisy quantum teleportation protocol (NTP) in which noise factors are corresponded to noisy channels, imperfect measurement and non-maximally entangled channel (isotropic channel). Evolution of entanglement between every two parts of three-partite density matrix changing through five steps of NTP is considered employing concurrence and negativity measures. Then results of concurrence and negativity are evaluated and compared by mutual information as a criterion of correlation. We illustrate the necessity of entanglement in the middle steps of NTP.
Quantum Network via Partial Entangled State
Journal of Communications, 2014
Abstractï€ -In this article we designed a quantum network consists of four nodes using pairs of partial entangled state (Werner-state). The nodes of this network are connected via Dzyaloshiniskii-Moriya (DM) interaction. The entanglement is quantified between all different nodes using Wootters concurrence. It is shown that there is a maximum entangled state generated between two nodes which are connected indirectly. The degree of entanglement depends on the direction of switching the interaction.
Entanglement routers via a wireless quantum network based on arbitrary two qubit systems
Physica Scripta, 2014
A wireless quantum network is generated between multi-hop, where each hop consists of two entangled nodes. These nodes share a finite number of entangled two qubit systems randomly. Different types of wireless quantum bridges are generated between the non-connected nodes. The efficiency of these wireless quantum bridges to be used as quantum channels between its terminals to perform quantum teleportation is investigated. We suggest a theoretical wireless quantum communication protocol to teleport unknown quantum signals from one node to another, where the more powerful wireless quantum bridges are used as quantum channels. It is shown that, by increasing the efficiency of the sources which emit the initial partial entangled states, one can increase the efficiency of the wireless quantum communication protocol.
2002
Quantum teleportation is possible because entanglement allows a definition of precise correlations between the noncommuting properties of a local system and corresponding noncommuting properties of a remote system. In this paper, the exact causality achieved by maximal entanglement is analyzed and the results are applied to the transfer of effects acting on the entanglement distribution channels to the teleported output state. In particular, it is shown how measurements performed on the entangled system distributed to the sender provide information on the teleported state while transferring the corresponding backaction to the teleported quantum state.
Routing entanglement in the quantum internet
npj Quantum Information
Remote quantum entanglement can enable numerous applications including distributed quantum computation, secure communication, and precision sensing. We consider how a quantum network-nodes equipped with limited quantum processing capabilities connected via lossy optical links-can distribute high-rate entanglement simultaneously between multiple pairs of users. We develop protocols for such quantum "repeater" nodes, which enable a pair of users to achieve large gains in entanglement rates over using a linear chain of quantum repeaters, by exploiting the diversity of multiple paths in the network. Additionally, we develop repeater protocols that enable multiple user pairs to generate entanglement simultaneously at rates that can far exceed what is possible with repeaters time sharing among assisting individual entanglement flows. Our results suggest that the early-stage development of quantum memories with short coherence times and implementations of probabilistic Bell-state measurements can have a much more profound impact on quantum networks than may be apparent from analyzing linear repeater chains. This framework should spur the development of a general quantum network theory, bringing together quantum memory physics, quantum information theory, quantum error correction, and computer network theory.