The most successful practical applications of quantum mechanics in information theory have been in the field of communication. This is a very old field that has taken inputs from engineering, pure mathematics and computer science apart from physics. It is only natural that application of quantum techniques here should be among the first to be considered and implemented. Modern technology in optical communication using laser light and optical fiber cables is sufficiently advanced that it can quickly be adapted to using photons as the quantum carriers of information.
The most successful practical applications of quantum mechanics in information theory have been in the field of communication. This is a very old field that has taken inputs from engineering, pure mathematics and computer science apart from physics. It is only natural that application of quantum techniques here should be among the first to be considered and implemented. Modern technology in optical communication using laser light and optical fiber cables is sufficiently advanced that it can quickly be adapted to using photons as the quantum carriers of information.
Quantum mechanics is the most successful theory for describing the microworld of photons, atoms, and their aggregates. It is behind much of the successes of modern technology. It has deep philosophical implications to the fundamental nature of material reality. A few decades ago, it was also realized that it is connected to the computer science and information theory. With this understanding were born the new disciplines of quantum computing and quantum communication. The current book introduces the very exciting area of quantum communication, which lies at the intersection of quantum mechanics, information theory, and atomic physics. The relevant concepts of these disciplines are explained, and their implication for the task of unbreakably secure communication is elucidated. The mathematical formulation of various approaches has been explained. An attempt has been made to keep the exposition self-contained. A senior undergraduate with good mathematics and physics background should be able to follow the current thinking about these issues after understanding the material presented in this book.
Quantum information has dramatically changed information science and technology, looking at the quantum nature of the information carrier as a resource for building new information protocols, designing radically new communication and computation algorithms, and ultra-sensitive measurements in metrology, with a wealth of applications. From a fundamental perspective, this new discipline has led us to regard quantum theory itself as a special theory of information, and has opened routes for exploring solutions to the tension with general relativity, based, for example, on the holographic principle, on non-causal variations of the theory, or else on the powerful algorithm of the quantum cellular automaton, which has revealed new routes for exploring quantum fields theory, both as a new microscopic mechanism on the fundamental side, and as a tool for efficient physical quantum simulations for practical purposes. In this golden age of foundations, an astonishing number of new ideas, frameworks, and results, spawned by the quantum information theory experience, have revolutionized the way we think about the subject, with a new research community emerging worldwide, including scientists from computer science and mathematics.
I nformation is an idea created in human brain. But information has physical aspects too. Emergence of new theory and technology in physical science always contribute to shape various theories, models and services in LIS. Shannon’s mathematical formula derives strength from the physical aspect of data or information and gives a new information theoretic approach to communication model by introducing concepts of bit and entropy. With the advancement of Quantum mechanics a new quantum mechanical model is under preparation. Phenomenon like quantum entanglement is successfully being used in computer technology which in turn helps reshape many LIS services. Quantum information science is a newly flourishing field which is expected to bring great advancements in information organization, processing, retrieval, automatic classification, NLP and other LIS related problems.
Scientific progress in physics and mathematics has led to the development of efficient technology for communicating and distributing information in the 20th century. This technology forms one of the cornerstones of information society and our global economy, which are highly reliant on secure methods to transfer and distribute information quickly. To satisfy ever-increasing demands for speed and security, encryption and communication methods are constantly improved and there is an ongoing effort to develop corresponding technology further. Classical information theory is not usually part of a physics undergraduate degree course. The theory assumes simple classical properties of physical systems and based on those a largely mathematical theory of information is established. The obtained results are independent of the chosen implementation and its physical details. However, one still has to acknowledge that information is physical, that is information carriers, senders, and receivers obey the laws of physics. The notion of quantum information comes about since it turns out that the rules of quantum mechanics violate some of the basic physics assumptions in classical information theory. The consequences of this are many, ranging from improved channel capacities, the possibility of physically secure communication protocols, to invalidating some beliefs about the security of classical communication protocols. So far the approach followed in this book was to assume idealized physical systemswhich perfectly implement qubits and then demonstrate how quantum computing algorithms can be realized using perfect qubits. Error correction and fault tolerance were only mentioned briefly.
Over the past century, quantum theory has taken flight from conceptual breakthroughs, such as wave–particle duality, quantisation of energy, and the uncertainty principle, to practical tools that are the backbone of modern electronics, lasers, semiconductors, and precision measurement systems. In the twenty-first century, this progress under the regime of the second quantum revolution has acquired the ability to directly control, manipulate, and engineer individual quantum systems.Quantum technologies found their pillars in quantum properties, such as superposition, entanglement, and coherence and have exceeded the boundaries of classical physics. The steady theoretical advances, combined with experimental progress, have brought quantum concepts closer to real-life use. Significant progress has made in filed of computation, communication, sensing, navigation, medicine, cyber security, and national defense undr the guidance of quantum technology.This book chapter presents a comprehensive and pedagogical overview of quantum technologies. It highlights quantum computing, quantum communication, and quantum sensing and metrology. The shift of quantum mechanics into practical applications is discussed. Current research trends are reviewed alongside the technological and engineering challenges. The critical issues, such as decoherence, scalability, error correction, standardisation, and workforce development, are discussed, which further highlights the need for global collaboration. Both National governments and the private sector are investing heavily in quantum research. This will act as a booster for quantum technologies to revolutionise information processing, secure communications, and precision measurements. Consequently and will significantly impact the scientific and technological landscape.
Over the past century, quantum theory has taken flight from conceptual breakthroughs, such as wave–particle duality, quantisation of energy, and the uncertainty principle, to practical tools that are the backbone of modern electronics, lasers, semiconductors, and precision measurement systems. In the twenty-first century, this progress under the regime of the second quantum revolution has acquired the ability to directly control, manipulate, and engineer individual quantum systems. Quantum technologies found their pillars in quantum properties, such as superposition, entanglement, and coherence and have exceeded the boundaries of classical physics. The steady theoretical advances, combined with experimental progress, have brought quantum concepts closer to real-life use. Significant progress has made in filed of computation, communication, sensing, navigation, medicine, cyber security, and national defense undr the guidance of quantum technology. This book chapter presents a comprehensive and pedagogical overview of quantum technologies. It highlights quantum computing, quantum communication, and quantum sensing and metrology. The shift of quantum mechanics into practical applications is discussed. Current research trends are reviewed alongside the technological and engineering challenges. The critical issues, such as decoherence, scalability, error correction, standardisation, and workforce development, are discussed, which further highlights the need for global collaboration. Both National governments and the private sector are investing heavily in quantum research. This will act as a booster for quantum technologies to revolutionise information processing, secure communications, and precision measurements. Consequently and will significantly impact the scientific and technological landscape.