1,721,004 research outputs found
Quantum Switch for the Quantum Internet: Noiseless Communications through Noisy Channels
No full textCounter-intuitively, quantum mechanics enables quantum particles to propagate simultaneously among multiple space-time trajectories. Hence, a quantum information carrier can travel through different communication channels in a quantum superposition of different orders, so that the relative causal order of the communication channels becomes indefinite. This is realized by utilizing a quantum device known as quantum switch. In this paper, we investigate, from a communications engineering perspective, the use of the quantum switch within the quantum teleportation process, one of the key functionalities of the Quantum Internet. Specifically, a theoretical analysis is conducted to quantify the performance gain that can be achieved by employing a quantum switch for the entanglement distribution process within the quantum teleportation, with respect to the case of absence of the quantum switch. The analysis reveals that, by utilizing the quantum switch, the quantum teleportation is heralded as a noiseless communication process with a probability that, remarkably and counter-intuitively, increases with the noise levels affecting the communication channels considered in the indefinite-order combination
Self-organizing strategy design for heterogeneous coexistence in the Sub-6 GHz
No full textDue to the worldwide ongoing pressure to massively exploit the Sub-6 GHz spectrum for the deployment of independently-operated and heterogeneous networks, innovative solutions for network coexistence are deeply required. Hence, in this paper, we design a self-organizing strategy with the aim of minimizing the coexistence interference among heterogeneous networks sharing the Sub-6 GHz spectrum. The design is performed under the constraints of promoting selfless network utilization and avoiding any direct communication among the heterogeneous networks. For this, we develop an analytical framework, grounded on the nest-site selection behavior observed in honeybee swarms, to model the coexistence problem among multiple heterogeneous networks. Specifically, first, different heterogeneous networks are mapped into different populations and the allocation of a Sub-6 GHz band to a network is mapped into the population commitment. Then, the evolution of the commitment process is described through a multi-dimensional differential system. We analytically study the stability of such a system at the equilibrium, and we derive the conditions that assure the optimal allocation of the available Sub-6 GHz bands among the different heterogeneous networks. Finally, the proposed strategy is validated through an extensive performance evaluation
Toward the Quantum Internet: A Directional-dependent Noise Model for Quantum Signal Processing
No full textAfter decades of pure science phase, the research on quantum technologies is finally reaching the engineering phase, getting out of the labs into business reality. Quantum technologies relies on quantum bits, aka qubits, which are the equivalent of classical bits used in classical information processing. Similarly to bits, the information stored in qubits can be corrupted by classical noise. Differently from bits, qubits are also vulnerable to quantum noise, a type of noise with no counterpart in the classical world. Hence, it becomes crucial to understand, from an engineering perspective, how the quantum noise corrupts the information stored within a qubit. To this aim, in this invited paper, we overview the effects of the quantum noise on an arbitrary qubit from a signal-processing perspective
When Entanglement Meets Classical Communications: Quantum Teleportation for the Quantum Internet
No full textQuantum Teleportation is the key communication functionality of the Quantum Internet, allowing the 'transmission' of qubits without the physical transfer of the particle storing the qubit. Quantum teleportation is facilitated by the action of quantum entanglement, a somewhat counter-intuitive physical phenomenon with no direct counterpart in the classical word. As a consequence, the very concept of the classical communication system model has to be redesigned to account for the peculiarities of quantum teleportation. This re-design is a crucial prerequisite for constructing any effective quantum communication protocol. The aim of this manuscript is to shed light on this key concept, with the objective of allowing the reader: i) to appreciate the fundamental differences between the transmission of classical information versus the teleportation of quantum information; ii) to understand the communications functionalities underlying quantum teleportation, and to grasp the challenges in the design and practical employment of these functionalities; iii) to acknowledge that quantum information is subject to the deleterious effects of a noise process termed as quantum decoherence. This imperfection has no direct counterpart in the classical world; iv) to recognize how to contribute to the design and employment of the Quantum Internet
How Deep the Theory of Quantum Communications Goes: Superadditivity, Superactivation and Causal Activation
No full textIn the theory of quantum communications, a deeper structure has been recently unveiled, showing that the capacity does not completely characterize the channel ability to transmit information due to phenomena - namely, superadditivity, superactivation and causal activation - with no counterpart in the classical world. Although how deep goes this structure is yet to be fully uncovered, it is crucial for the communication engineering community to own the implications of these phenomena for understanding and deriving the fundamental limits of communications. Hence, the aim of this treatise is to shed light on these phenomena by providing the reader with an easy access and guide towards the relevant literature and the prominent results from a communication engineering perspective
Direct Quantum Communications in the Presence of Realistic Noisy Entanglement
No full textTo realize the Quantum Internet, quantum communications require pre-shared entanglement among quantum nodes. However, both the generation and the distribution of the maximally-entangled quantum states are inherently contaminated by quantum decoherence. Conventionally, the quantum decoherence is mitigated by performing the consecutive steps of quantum entanglement distillation followed by quantum teleportation. However, this conventional approach imposes a long delay. To circumvent this impediment, we propose a novel quantum communication scheme relying on realistic noisy pre-shared entanglement, which eliminates the sequential steps imposing delay in the standard approach. More precisely, our proposed scheme can be viewed as a direct quantum communication scheme capable of improving the quantum bit error ratio (QBER) of the logical qubits despite relying on realistic noisy pre-shared entanglement. Our performance analysis shows that the proposed scheme offers competitive QBER, yield, and goodput compared to the existing state-of-the-art quantum communication schemes, despite requiring fewer quantum gates
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Experiencing the communication advantage of the Superposition of Causal Orders
No full textMany recent studies deal with the Superposition of Causal Orders, a quantum operation with promising advantages in both communication or computing. To experience the advantages, there are several way of implementing it. In literature, most of the set-ups are photonic-based. Instead, our interest is witnessing the Superpositon of Causal Orders within a programmable technology, based on superconductors. To do that, we focus on a specific case of the subject operation, which could be useful for the future of quantum communication
From the Environment-Assisted Paradigm to the Quantum Switch
No full textThe quantum switch has been witnessing growing attention in the last years due to its advantage in several quantum technologies applications. In particular, it has been proven that the quantum switch can significantly improve the communication rates beyond the limits of conventional quantum Shannon theory. In this paper, we theoretically prove that the quantum switch can be interpreted as a particular instance of the Environment-assisted quantum communication paradigm. The developed analysis is crucial to better understand the limitations of the quantum switch. Furthermore, the analysis is key to shed the light on control strategies within the Environment-assisted communication paradigm
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