This book explores alternative ways of accomplishing secure information transfer with incoherent multi-photon pulses in contrast to conventional Quantum Key Distribution techniques. Most of the techniques presented in this book do not need conventional encryption. Furthermore, the book presents a technique whereby any symmetric key can be securely transferred using the polarization channel of an optical fiber for conventional data encryption. The work presented in this book has largely been practically realized, albeit in a laboratory environment, to offer proof of concept rather than building a rugged instrument that can withstand the rigors of a commercial environment.

Light and light based technologies have played an important role in transforming our lives via scientific contributions spanned over thousands of years. In this book we present a vast collection of articles on various aspects of light and its applications in the contemporary world at a popular or semi-popular level. These articles are written by the world authorities in their respective fields. This is therefore a rare volume where the world experts have come together to present the developments in this most important field of science in an almost pedagogical manner. This volume covers five aspects related to light. The first presents two articles, one on the history of the nature of light, and the other on the scientific achievements of Ibn-Haitham (Alhazen), who is broadly considered the father of modern optics. These are then followed by an article on ultrafast phenomena and the invisible world. The third part includes papers on specific sources of light, the discoveries of which have revolutionized optical technologies in our lifetime. They discuss the nature and the characteristics of lasers, Solid-state lighting based on the Light Emitting Diode (LED) technology, and finally modern electron optics and its relationship to the Muslim golden age in science. The book’s fourth part discusses various applications of optics and light in today's world, including biophotonics, art, optical communication, nanotechnology, the eye as an optical instrument, remote sensing, and optics in medicine. In turn, the last part focuses on quantum optics, a modern field that grew out of the interaction of light and matter. Topics addressed include atom optics, slow, stored and stationary light, optical tests of the foundation of physics, quantum mechanical properties of light fields carrying orbital angular momentum, quantum communication, and Wave-Particle dualism in action.

The field of quantum computing has experienced rapid development and many different experimental and theoretical groups have emerged worldwide.This book presents the key elements of quantum computation and communication theories and their implementation in an easy-to-read manner for readers coming from physics, mathematics and computer science backgrounds. Integrating both theoretical aspects and experimental verifications of developing quantum computers, the author explains why particular mathematical methods, physical models and realistic implementations might provide critical steps towards achieving the final goal - constructing quantum computers and quantum networks. The book serves as an excellent introduction for new researchers and also provides a useful review for specialists in the field

Quantum information processing offers fundamental improvements over classical information processing, such as computing power, secure communication, and high-precision measurements. However, the best way to create practical devices is not yet known. This textbook describes the techniques that are likely to be used in implementing optical quantum information processors. After developing the fundamental concepts in quantum optics and quantum information theory, the book shows how optical systems can be used to build quantum computers according to the most recent ideas. It discusses implementations based on single photons and linear optics, optically controlled atoms and solid-state systems, atomic ensembles, and optical continuous variables. This book is ideal for graduate students beginning research in optical quantum information processing. It presents the most important techniques of the field using worked examples and over 120 exercises.

Designed to offer a thorough account of the KLJN key exchange system (also known as the Kish Cypher, the Kish Key Distribution, etc.) and its unconditional security, this book explains the scheme's foundation in classical statistical physics and its superiority to its quantum-based competitors for particular applications, from the perspective of Dr. Kish himself.This book clarifies the misinformation behind heated debates on the 'Kish Cypher' (the popular but incorrect name for the Kirchhoff-Law-Johnson-Noise, KLJN, scheme), and debunks common misconceptions by using simple and clear-cut treatments to explain the protocol's working principle — an understanding that has eluded (even) several experts of computer science, quantum security, and electrical engineering. The work also explains how the scheme can provide the same (or higher) level of security as quantum communicators at a thousandth of the cost.The contents of this text address both layman and expert levels of understanding.

This book traces the evolution of our understanding and utilization of light from classical antiquity and the early thoughts of Pythagoras to the present time. From the earliest recorded theories and experiments to the latest applications in photonic communication and computation, the ways in which light has been put to use are numerous and astounding. Indeed, some of the latest advances in light science are in fields that until recently belonged to the realm of science fiction. The author, writing for an audience of both students and other scientifically interested readers, describes fundamental investigations of the nature of light and ongoing methods to measure its speed as well as the emergence of the wave theory of light and the complementary photon theory. The importance of light in the theory of relativity is discussed as is the development of electrically-driven light sources and lasers. The information here covers the range o f weak single-photon light sources to super-high power lasers and synchrotron light sources. Many cutting-edge topics are also introduced, including entanglement-based quantum communication through optical fibers and free space, quantum teleportation, and quantum computing. The nature and use of "squeezed light" - e.g. for gravitational wave detection - is another fascinating excursion, as is the topic of fabricated metamaterials, as used to create invisibility cloaks. Here the reader also learns about the realization of extremely slow speed and time-reversed light. The theories, experiments, and applications described in this book are, whenever possible, derived from original references. The many annotated drawings and level of detail make clear the goals, procedures, and conclusions of the original investigators. Where they are required, all specialist terms and mathematical symbols are defined and explained. The final part of the book covers light expe riments in the free space of the cosmos, and also speculates about scenarios for the cosmological origins of light and the expected fate of the photon in a dying universe.

This two-volume set LNCS 12239-12240 constitutes the refereed proceedings of the 6th International Conference on Artificial Intelligence and Security, ICAIS 2020, which was held in Hohhot, China, in July 2020. The conference was formerly called “International Conference on Cloud Computing and Security” with the acronym ICCCS. The total of 142 full papers presented in this two-volume proceedings was carefully reviewed and selected from 1064 submissions. The papers were organized in topical sections as follows: Part I: Artificial intelligence and internet of things. Part II: Internet of things, information security, big data and cloud computing, and information processing.

The accelerating pace at which quantum computing is developing makes it almost inevitable that some of the major cryptographic algorithms and protocols we rely on daily, for everything from internet shopping to running our critical infrastructure, may be compromised in the coming years. This book presents 11 papers from the NATO Advanced Research Workshop (ARW) on Quantum and Post-Quantum Cryptography, hosted in Malta in November 2021. The workshop set out to understand and reconcile two seemingly divergent points of view on post-quantum cryptography and secure communication: would it be better to deploy post-quantum cryptographic (PQC) algorithms or quantum key distribution (QKD)? The workshop brought these two communities together to work towards a future in which the two technologies are seen as complementary solutions to secure communication systems at both a hardware (QKD) and software (PQC) level, rather than being in competition with each other. Subjects include the education of an adequate workforce and the challenges of adjusting university curricula for the quantum age; whether PQC and QKD are both required to enable a quantum-safe future and the case for hybrid approaches; and technical aspects of implementing quantum-secure communication systems. The efforts of two NATO nations to address the possible emergence of cryptanalytically-relevant quantum computers are explored, as are two cryptographic applications which go beyond the basic goal of securing two-party communication in a post-quantum world. The book includes economic and broader societal perspectives as well as the strictly technical, and adds a helpful, new contribution to this conversation.

This book deals with applications in several areas of science and technology that make use of light which carries orbital angular momentum. In most practical scenarios, the angular momentum can be decomposed into two independent contributions: the spin angular momentum and the orbital angular momentum. The orbital contribution affords a fundamentally new degree of freedom, with fascinating and wide-spread applications. Unlike spin angular momentum, which is associated with the polarization of light, the orbital angular momentum arises as a consequence of the spatial distribution of the intensity and phase of an optical field, even down to the single photon limit. Researchers have begun to appreciate its implications for our understanding of the ways in which light and matter can interact, and its practical potential in different areas of science and technology.