This chapter delves into the intriguing connection between quantum mechanics and information. Building upon the receptive relation understanding of information, it sheds light on the prominence of the quantum mechanics of information in the early 20th century – this is the quantum mechanics manifestation of information as receptive relation. The chapter unveils the distinction between classical physics and quantum physics concerning information based on the receptive relation understanding: classical physics is the knowledge system that can be established by attributing receptive relation to objects, thus ignoring information; quantum physics is a knowledge system that cannot be established by attributing the receptive relation to objects and thus cannot ignore information. While information was presented in quantum theory, it was only discernible through data highlighting due to the veil of matter and energy. Exploring the mysterious “quantum information” holds great significance for both quantum physics and information theory. The secret of information as receptive relation lies in quantum observations. Quantum phenomenon itself is information as receptive relation. It is in this sense that quantum information is the manifestation of information; it is the emergence of quantum mechanics of information as receptive relation that lays the foundation for deepening the understanding of information and further studying its basic characteristics and information encoding.
This chapter delves into the intriguing connection between quantum mechanics and information. Building upon the receptive relation understanding of information, it sheds light on the prominence of the quantum mechanics of information in the early 20th century – this is the quantum mechanics manifestation of information as receptive relation. The chapter unveils the distinction between classical physics and quantum physics concerning information based on the receptive relation understanding: classical physics is the knowledge system that can be established by attributing receptive relation to objects, thus ignoring information; quantum physics is a knowledge system that cannot be established by attributing the receptive relation to objects and thus cannot ignore information. While information was presented in quantum theory, it was only discernible through data highlighting due to the veil of matter and energy. Exploring the mysterious “quantum information” holds great significance for both quantum physics and information theory. The secret of information as receptive relation lies in quantum observations. Quantum phenomenon itself is information as receptive relation. It is in this sense that quantum information is the manifestation of information; it is the emergence of quantum mechanics of information as receptive relation that lays the foundation for deepening the understanding of information and further studying its basic characteristics and information encoding.
Information is physical. Today’s information processing and communication are classical: they are based upon the laws of Newton’s and Maxwell’s classical physics. This assertion holds all the way, from commercial computers and networks, up to their most abstract models, e.g. Turing machines. Research in quantum information was born some twenty five years ago, with the encounter of two major scientific achievements of the 20th century, namely quantum physics and information sciences. A technological motivation for that is an extrapolation of Moore’s law which seems to indicate that the amount of matter needed for one bit will be reduced to one particle sometimes before year 2020. A deeper, scientific driving force of this interdisciplinary research is that of looking for the consequences of having computation and communication based directly upon the laws of quantum physics, i.e. our current ultimate knowledge of the world of elementary particles, as described by quantum mechanics. Breakthroughs in cryptography, communications, information theory and algorithmics have shown that this transplantation from classical to quantum has far reaching consequences, both quantitative and qualitative, and opens new avenues for research within the foundations of computer science and physics. The principles 388 and most striking results and hot topics of this promising way of encoding, processing and communicating information are briefly introduced in this chapter from a mostly computer science point of view, with detailed examples in algorithmics and in cryptography. At the end of the chapter, a short list of some significant articles, textbooks and reports on quantum information are suggested for further reading.
In this chapter, I will introduce the concepts of quantum information that are necessary to the understanding of quantum cryptography. I first review the main principles of quantum mechanics. I then introduce concepts that somehow translate information theory into the quantum realm and discuss their unique features. Finally, I conclude this chapter with some elements of quantum optics. Fundamental definitions in quantum mechanics In classical mechanics, a system is described with physical quantities that can take certain values at a given moment in time; we say that is has a state. For instance, the state of an elevator comprises its position and speed at a given time. As dictated by common sense, if the elevator is at a given height, it cannot be simultaneously found at another location. With quantum mechanics, things are fundamentally different and elementary particles can behave against common sense. For instance, a quantum system can simultaneously be in different levels of energy. This is not because our knowledge of the state of the system is incomplete: the behavior of the quantum system is consistent with the fact that it is in simultaneous levels of energy. It would go beyond the scope of this book to describe quantum mechanics in detail. Instead, I propose a synthetic introduction suitable for the understanding of quantum cryptography. For a more detailed introduction, please refer to the books listed at the end of this chapter.
There is no dissent regarding the quantum theory success on the small-scale structure of the world but there is equally an open subject of debate about its interpretation. Both quantum mechanics and the theory of relativity are indeed extensions of classical mechanics, that is, they reproduce their results in other appropriate limiting cases. Quantum mechanics provides a new set of laws and a method of description of microscopic systems that has been very successful. The chapter discusses some of the fundamental principles of this highly controversial subject. In quantum physics, it is difficult to uphold a sharp distinction between the object and the observer. The chapter examines why quantum mechanics seems to be so hard for newcomers to learn and understand. The theory of quantum mechanics has led to many applications: laser, the electron microscope and many other technological devices.
Newton's second law of motion, F = ma, has long been considered a cornerstone of classical mechanics, providing a fundamental framework for understanding the behavior of macroscopic objects. However, as physics delves into the quantum realm, the applicability of Newton's second law becomes limited, and the principles of quantum mechanics emerge as the dominant description of particle behavior. Beginning with an overview of the historical development of classical mechanics by Newton and the emergence of quantum mechanics in the early 20th century, the article delves into the foundational principles of framework. The classical description of particles as point masses with deterministic trajectories is contrasted with the probabilistic nature of quantum particles described by wave functions and superposition principles. Practical applications and implications of these theories are also discussed, shedding light on their significance in various scientific disciplines. This research article presents a comparative analysis of Newton's second law of motion and quantum physics, examining their fundamental principles and implications through the lens of classical and quantum mechanics. Beginning with an overview of Newton's second law and its significance in classical mechanics, the article delves into the foundational postulates of quantum mechanics and their departure from classical concepts. This explores the inherent limitations of Newton's second law when applied to quantum phenomena, comparing and contrasting its principles with those of quantum physics. Through a comprehensive analysis of evidence and theoretical frameworks, this article elucidates the boundaries of classical mechanics and highlights the need for quantum mechanics to describe phenomena at the atomic and subatomic levels. Through an exploration of key differences and similarities, this aims to provide insights into the behavior of particles at both macroscopic and microscopic scales
Quantum information stands apart from classical information, rooted in the principles of quantum mechanics and quantum information theory. Quantum states serve as the fundamental unit of quantum information, whose evolution is governed by the laws of quantum mechanics. While some philosophers, such as A. Duwell have argued that there is no quantum information, which is not a new concept and can be described using Shannon information theory, others, like C. M. Caves and C. A. Fuchs have proposed that quantum information represents classical information stored within quantum systems. However, this chapter argues that quantum information exists and is different from classical information from the perspectives of how information exists and how it is transmitted. Quantum information, unlike classical information, can be categorized into two kinds: Ontological quantum information and epistemological quantum information, where the former reflects the inherent state of microscopic particles, which is independent of observation, and the latter describes how we perceive their state through measurements. Finally, this chapter explores the connection between quantum information and quantum reality. Quantum reality refers to the show of the self-identity of quantum entities. Quantum information, on the other hand, is the show of the states and correlative ways of quantum entities, and it coexists with quantum reality.