The world is changing very fast, and so are the ways of communication and computation. This article is about a new communication and information technology based on the principles of the quantum physics. At first we discuss about some fundamental paradigms of Quantum Computers World, and then introducing the basis of quantum computation: "QBit". After that we explain some magic properties of this atomic QBit including quantum measurement, superposition, entanglement, etc. Then we introduce quantum gates the basic modules of the next generation computers, their relation with the ordinary logical gates and the properties of some of the most useful quantum gates. And finally, we have a brief talk on some magic algorithm and the relation between these new born creatures and other fields of computers world, based on the quantum theories and manipulated by the quantum circuits
The world is changing very fast, and so are the ways of communication and computation. This article is about a new communication and information technology based on the principles of the quantum physics. At first we discuss about some fundamental paradigms of Quantum Computers World, and then introducing the basis of quantum computation: "QBit". After that we explain some magic properties of this atomic QBit including quantum measurement, superposition, entanglement, etc. Then we introduce quantum gates the basic modules of the next generation computers, their relation with the ordinary logical gates and the properties of some of the most useful quantum gates. And finally, we have a brief talk on some magic algorithm and the relation between these new born creatures and other fields of computers world, based on the quantum theories and manipulated by the quantum circuits
Quantum computing uses quantum-mechanical principles to enable new models of computation bexond the classical paradigm. This article presents an accessible introduction to the mathematical and conceptual foundations of quantum computing, covering qubits, quantum gates, multi-qubit systems, entanglement, and measurement. The gate-based computation model and quantum circuits are introduced, together with key notations such as universality and reversibility. As an illustrative example, the Deutsch-Josza algorithm is discussed to demonstrate how quantum algorithm can be constucted. The article concludes with a brief overview of the current state and challenges of quantum computing.
transmission of quantum states by using entanglement.Quantum error correction keeps the possibility of maintaining quantum coherence when an irreversible noise process exists.At present, the world is undergoing a new round of "quantum revolution".Quantum computing and communication technologies are accelerating breakthroughs in key technologies.In the new stage, some technologies are gradually being integrated with the system.Breakthroughs have been made in key technologies, such as integration, engineering, and networking.The integration of quantum communication with classical communication networks, multi-bit operation, and computing of quantum computers show the application prospects of quantum information in the industry. Brief introduction of the bookIn this book, we will introduce some fundamental quantum computing and communication technologies that will form the basis for much of what follows.After this brief introduction, we will review the basic conception and relevance of quantum algorithms, quantum computer, quantum code, post-quantum cryptography, quantum key distribution, and quantum teleportation respectively in detail.
Abstract: Quantum computing is a modern calculation method that is based on the science of quantum mechanics. These phenomena include the bizarre behavior of particles at the atomic and subatomic levels, and the way that these particles can be in multiple states simultaneously. The field of computer science is a great mix of physics, math, and information theory. This technology provides high computing power, low power consumption, and exponential speed by controlling the behavior of small physical objects, such as atoms. Atoms, electrons, photons, etc. are all elements of the physical world. We would like to introduce the basics of quantum computing, and some of the ideas behind it. This article begins with the origins of the classical computer and discusses all the improvements and transformations that have been made due to its limitations thus far, then moves on to the basic operations of quantum computing and results in quantum properties such as superposition, entanglement, and interference.
Quantum computing is considered as good mixture of quantum physics, computer science and information theories. This paper introduces fundamentals needed to understand different layers associated with quantum computing some of them are superposition, entanglement, quantum gates and circuit models like Grover’s algorithm, Shor’s algorithm. Thereafter, it will elaborate hurdles encounter in constructing a quantum computer like Constructing, verification, architecture, quantum error correction, compiler and programming issues. Finally some of the applications like quantum cryptography is discussed.
Over the last decade a new way to compute has been defined which, unlike conventional methods, is based on quantum mechanics rather than classical physics. This fundamental change in paradigm can, in principle, solve some important and hitherto intractable problems such as prime factorization of large numbers. This tutorial presentation will review the basics of quantum computation and the design of circuits to implement quantum algorithms. The starting point is the notion of a quantum bit or qubit. Because of the superposition property of quantum states, n qubits can store 2n numbers simultaneously, implying a type of massive parallelism. Furthermore, quantum states allow powerful forms of interaction such as entanglement that have no classical counterparts. Qubits are fragile, however, and are altered by measurement; hence quantum circuits must follow very different rules from classical ones. The differences between quantum and classical logic circuits will be discussed and illustrated. Finally, the physical implementation of quantum devices will be considered, along with the prospects for practical quantum computers.
The subject of quantum computing brings together ideas from classical information theory, computer science, and quantum physics. This review aims to summarize not just quantum computing, but the whole subject of quantum information theory. Information can be identified as the most general thing which must propagate from a cause to an effect. It therefore has a fundamentally important role in the science of physics. However, the mathematical treatment of information, especially information processing, is quite recent, dating from the mid-20th century. This has meant that the full significance of information as a basic concept in physics is only now being discovered. This is especially true in quantum mechanics. The theory of quantum information and computing puts this significance on a firm footing, and has led to some profound and exciting new insights into the natural world. Among these are the use of quantum states to permit the secure transmission of classical information (quantum cryptography), the use of quantum entanglement to permit reliable transmission of quantum states (teleportation), the possibility of preserving quantum coherence in the presence of irreversible noise processes (quantum error correction), and the use of controlled quantum evolution for efficient computation (quantum computation). The common theme of all these insights is the use of quantum entanglement as a computational resource. It turns out that information theory and quantum mechanics fit together very well. In order to explain their relationship, this review begins with an introduction to classical information theory and computer science, including Shannon's theorem, error correcting codes, Turing machines and computational complexity. The principles of quantum mechanics are then outlined, and the Einstein, Podolsky and Rosen (EPR) experiment described. The EPR-Bell correlations, and quantum entanglement in general, form the essential new ingredient which distinguishes quantum from classical information theory and, arguably, quantum from classical physics. Basic quantum information ideas are next outlined, including qubits and data compression, quantum gates, the `no cloning' property and teleportation. Quantum cryptography is briefly sketched. The universal quantum computer (QC) is described, based on the Church-Turing principle and a network model of computation. Algorithms for such a computer are discussed, especially those for finding the period of a function, and searching a random list. Such algorithms prove that a QC of sufficiently precise construction is not only fundamentally different from any computer which can only manipulate classical information, but can compute a small class of functions with greater efficiency. This implies that some important computational tasks are impossible for any device apart from a QC. To build a universal QC is well beyond the abilities of current technology. However, the principles of quantum information physics can be tested on smaller devices. The current experimental situation is reviewed, with emphasis on the linear ion trap, high- Q optical cavities, and nuclear magnetic resonance methods. These allow coherent control in a Hilbert space of eight dimensions (three qubits) and should be extendable up to a thousand or more dimensions (10 qubits). Among other things, these systems will allow the feasibility of quantum computing to be assessed. In fact such experiments are so difficult that it seemed likely until recently that a practically useful QC (requiring, say, 1000 qubits) was actually ruled out by considerations of experimental imprecision and the unavoidable coupling between any system and its environment. However, a further fundamental part of quantum information physics provides a solution to this impasse. This is quantum error correction (QEC). An introduction to QEC is provided. The evolution of the QC is restricted to a carefully chosen subspace of its Hilbert space. Errors are almost certain to cause a departure from this subspace. QEC provides a means to detect and undo such departures without upsetting the quantum computation. This achieves the apparently impossible, since the computation preserves quantum coherence even though during its course all the qubits in the computer will have relaxed spontaneously many times. The review concludes with an outline of the main features of quantum information physics and avenues for future research.