IET Quantum Communication最新文献

In the past few years, CMOS semiconductor has been a growing and evolving technology in VLSI. However, due to the scaling issue and some other constraints like heat generation, high power consumption QCA (quantum cellular automata) emerged as an alternate and enhanced solution that provides a new technique of computing than CMOS in recent years. QCA is highly effective in implementing both Irreversible and Reversible logic, which has been shown to be incredibly efficient in terms of power consumption. A novel technique to data encryption called as SCV (select, cross, and variation) is demonstrated in this paper, which is based on ASCII to binary conversion and uses reversible logic. The data security procedure is aided by implementing SCV logic in reversible logic. Using Fredkin gate, it is built in QCA. QCADesigner tool has been used here for design and verification purposes. Total 80 cell counts and 0.14 μm² area are required. The theoretical data and the simulation results are the same as the intended circuit. Comparison to previous QCA architectural features is featured.

Quantum communication networks pose immense potential for revolutionising secure communications for several applications such as banking, defence, etc. The majority literature on quantum networks deals with the problems of networking and resource allocation using Software Defined Networks (SDNs). SDNs, however, introduce several issues, such as app manipulation attacks and scalability issues. We propose a novel scheme of implementing quantum communication networks that are hardware routed rather than software defined by labelling qubit photons using laser communications. We provide a comprehensive implementation of the new scheme and propose two novel algorithms—Bandwidth sharing and Equitable bandwidth sharing to implement the hardware routed quantum network. The algorithms result in a key rate increase of 118% and improved network resource utilization of 147% as compared to the First Come First Serve algorithm.

In the general theory of relativity, the four-dimensional space-time of describing a mass body accelerated motion or in a gravitational field, although it is a curved Riemannian geometric space from the perspective of “integral geometry”, but for any instantaneous position of the moving mass body, there is a local Flat Space of Riemannian geometric space. The local Flat Space is a Mincowski space in which the inertial coordinate system can be used in the local small area. Between the proper coordinate systems of two interacting moving masses, or between a series of following proper coordinate systems experienced by a mass body moving in any way, there should be a coordinate transformation relationship similar to the traditional special theory of relativity. However, they have an important difference: in these instantaneous local inertial systems, the speed of light is no longer the constant c of vacuum, the effect of gravitational field or acceleration on the speed of light is the same as that of a medium with a dielectric constant of ε and a magnetic permeability of μ. Using the special theory of relativity with variable speed of light that the author has established can discuss relevant relativity physics issues in these instantaneous local inertial systems. This article uses the special theory of relativity with variable speed of light to derive the functional relationship between a moving mass and the change of speed. In addition to obtain the traditional continuous increasing function relationship, a step function relationship with stepped discontinuous changes is also obtained. At the same speed, the mass can have two values, such as a ladder upgrade one level; the same mass can be matched with two different speeds, such as one step extension forward on the same step stair. From the perspective of the increase in speed, the mass is stagnant on the step platform (the speed increases, the mass does not change), and it jumps in the step up ladder (the speed does not change, the mass has a jump change). This obviously incorporates the main image of quantum theory into the theory of relativity, which is the result that all physics researchers care about and expect.

Quantum Computing has emerged as one of the important dimensions of global research lately, on both the prospects, hardware as well as algorithms. With enhanced processing powers, several architectures based on adiabatic concepts resulting in reversibility have been proposed to date. Architectures based on Quantum Dot Cellular Automata have also shown considerable promise for realising the concept of reversibility. Recently, research has been focussed on the application of quantum computing for faster and secure communication. Dedicated machine learning algorithms and neural networks for quantum computation have also attracted considerable research. With a plethora of research and advances in this domain, this Special Issue publishes outstanding contributions for dissemination of the knowledge of Reversible Quantum Communication & Systems. This Special Issue publishes latest approaches and findings in Quantum Algorithms and Reversible Computing with focus on emerging Machine Learning approaches in Quantum Communications. Reversible Logic forms a pivotal part of Quantum Computing and has been a topic of high interest among Quantum Computing Scientists and researchers throughout the last decade. It also exhibits considerable prospects in recent research due to its adiabatic characteristics. Logic synthesis and optimisation algorithms within the purview of Reversibility have witnessed credible approaches and pose future prospects, such as the rise of Machine Learning approaches which have also penetrated the Quantum Domain.

Any technology offering zero power dissipation must be reversible. A reversible circuit can be envisaged as a cascade of reversible gates only, such as Toffoli gate, which has two components: k control bits and a target bit (k-CNOT), k ≥ 1. Analysing testability issues in a reversible circuit is an important phenomenon. A new online design-for-testability (DFT) technique for reversible circuits is proposed. The authors’ method yields less overhead in terms of quantum cost as compared to the previous online approaches.

Due to the difficulties of implementing joint measurements, quantum illumination schemes that are based on signal-idler entanglement are difficult to implement in practice. For this reason, one may consider quantum-inspired designs of quantum lidar/radar where the input sources are semi-classical (coherent states) while retaining the quantum aspects of the detection. The performance of these designs could be studied in the context of asymmetric hypothesis testing by resorting to the quantum Stein’s lemma. However, here the authors discuss that, for typical finite-size regimes, the second- and third-order expansions associated with this approach are not sufficient to prove quantum advantage.

Physics in general is successfully governed by quantum mechanics at the microscale and principles of relativity at the macroscale. Any attempts to unify them using conventional methods have somewhat remained elusive for nearly a century up to the present stage. Here, a classical gedanken experiment of electron-wave diffraction of a single slit is intuitively examined for its quantized states. A unidirectional monopole pair (MP) field as quanta of the electric field is pictorially conceptualised into 4D space-time. Its application towards quantum mechanics and general relativity appears consistent with existing knowledge in physics. This considers a multiverse of MP models at a hierarchy of scales. Einsteinian gravity is then defined to be of circular acceleration with angular momentum in time reversal mode to an overarching MP field precessing into forward time. Such descriptions provide a credible intuitive tool for physics applications in general. Its proposed design can be assessed using conventional methods, perhaps in incremental steps and this warrants further investigations.

As quantum computers are based on the laws of quantum mechanics, they are capable of solving certain problems faster than their classical counterparts. However, quantum algorithms with a theoretical speed-up often assume that data can be loaded efficiently. In general, the runtime complexity of the loading routine depends on (i) the data encoding that defines how the data is represented by the state of the quantum computer and (ii) the data itself. In some cases, loading the data requires at least exponential time that destroys a potential speed-up. And especially for the first generation of devices that are currently available, the resources (qubits and operations) needed to encode the data are limited. In this work, we, therefore, present six patterns that describe how data is handled by quantum computers.

Finding cliques in a graph has a wide range of applications due to its pattern matching ability. The k-clique problem, a subset of the clique problem, determines whether or not an arbitrary network has a clique of size k. Modern-day applications include a variation of the k-clique problem that lists all cliques of size k. However, the quantum implementation of such a variation of the k-clique problem has not been addressed yet. In this work, apart from the theoretical solution of such a k-clique problem, practical quantum-gate-based implementation has been addressed using Grover's algorithm. In a classical-quantum hybrid architecture, this approach is extended to build the circuit for the maximum clique problem. Our technique is generalised since the program automatically builds the circuit for any given undirected and unweighted graph and any chosen k. For a small k with regard to a big graph, the proposed solution to addressing the k-clique issue has shown a reduction in qubit cost and circuit depth when compared to the state-of-the-art approach. A framework is also presented for mapping the automated generated circuit for clique problems to quantum devices. Using IBM's Qiskit, an analysis of the experimental results is demonstrated.