Kvantefysik (kvantemekanik og kvantefeltteori)

Do we have free will? Is the universe compatible with God? Do we live in a computer simulation? Does the universe think?Physicists are great at complicated research, but they are less good at telling us why it matters. In this entertaining and groundbreaking book, theoretical physicist Sabine Hossenfelder breaks down why we should care. Drawing on the latest research in quantum mechanics, black holes, string theory and particle physics, Existential Physics explains what modern physics can tell us about the big questions.Filled with counterintuitive insights and including interviews with other leading scientists, this clear and yet profound book will reshape your understanding of science and the limits of what we can know.

100 års kvantemekanik har været et overflødighedshorn af overraskelser. Lige siden videnskabshistoriens mest succesrige teori blev skabt i København i 1920’erne har den været ombrust af debat. Filosofiske fortolkninger, vidunderlig fysik, teknologiske chok såsom atombomben og et helt nyt bud på computerens fremtid. Kvantefysikken bliver ved med at yde. Dens sære og mærkelige form for matematik viser sig nu at ligne hverdagsoplevelser i menneskesindet mere end nogen skulle have troet. I syv sind tegner et billede af de mangfoldige og modsætningsfyldte særpræg ved atomernes fysik og menneskers måde at opleve verden på. Men også en advarsel om at tidens store begejstring for kvanteteknologier kan vise sig overophedet. Der er brug for en demokratisk debat om kunstig intelligens og kvantecomputere.  Tor Nørretranders skrev i 1985 Det udelelige – Niels Bohrs aktualitet i fysik, mystik og politik (genudgivet i 2022). Den fortalte historien om den dengang oversete fysisk forskning, der i december 2022 blev hædret med Nobelprisen i fysik. I syv sind fortsætter den forunderlige historie.

‘Hverdagsmad fra River Cottage’ er den ultimative grundkogebog for alle, der har en holdning til den mad, de spiser til daglig. Heri er samlet Hugh Fearnley-Whittingstalls bedste bud på økonomisk, sund og velsmagende hverdagsmad – og alle kan være med. Den frygtløse kok Hugh Fearnley-Whittingstall er kendt fra DR2’s programserie ‘River Cottage’, hvor han har lært danskerne om bedre madvaner, bæredygtighed og vigtigheden af gode råvarer. Ifølge Hugh er det nemlig sådan, at ændrer man menneskers holdning til mad, ændrer man deres holdning til livet! Og det er netop udgangspunktet for denne kogebog fra River Cottage, der med massevis af lækre opskrifter og tips til hverdagen giver et bud på en sundere hverdagskost for alle. Det er mad med holdning og velsmag.

Kvantefysik er overalt omkring os. Det er grundlaget for vores forståelse af naturlovene, fra atomers opførsel til hele universets. Men kvanteuniverset forbliver indhyllet i mystik ved at påstå, at en partikel kan være to steder på samme tid, eller at en kat kan være både død og levende.Tag med på et eventyr for at møde pionererne – Bohr, Einstein, Heisenberg og andre – inden for den moderne fysik på en svimlende rejse, der viser kvanteunivesets uendelige mangfoldighed.Skrevet af Thibault Damour, teoretisk fysiker og professor ved Institutdes Hautes Etudes Scientifiques og medlem af det franske Académiedes Sciences. Han er kendt verden over for sit banebrydende arbejde med sorte huller, pulsarer, gravitationsbølger og kvantekosmologi. Han har modtaget adskillige priser, herunder den prestigefyldte Einsteinmedalje.Tegnet af Mathieu Burniat, der i Frankrig er kendt for sine populærhistoriske fortællinger, der ud over "Kvanteuniverset" også afspejler hans interesser i gastronomi ("La Passion de Dodin-Bouffant "), naturen ("Sous terre") og vores hjernes funktion ("Une mémoire de roi ").

Quantum Supremacy: How the Quantum Computer Revolution Will Change Everything is a groundbreaking book penned by the renowned physicist, Michio Kaku. Published by DOUBLEDAY & CO in 2023, this book delves into the fascinating world of quantum computing and its potential to revolutionize our lives. The book is a must-read for those who are interested in the intersection of science, technology, and the future. Kaku, with his knack for simplifying complex scientific concepts, takes readers on an exciting journey through the quantum realm. He discusses how quantum supremacy - the point where quantum computers surpass traditional computers in computational ability - will change everything from medicine to cryptography. This English language book is not just for tech enthusiasts but also for anyone curious about the future of technology and its impact on society. Don't miss out on this intriguing exploration of quantum computing, brought to you by DOUBLEDAY & CO.

En forårsaften i København 1925. En ung tysk videnskabsmand har en hel nat diskuteret atomfysik med sin mentor, professoren på Institut for Teoretisk Fysik. I Fælledparken ser den unge fysiker en mand, der bevæger sig ind og ud af gadelygternes lyskegler. En tilfældighed, der for altid vil ændre vores verdensbillede.Christian Haller – en af Schweiz’ mest velansete forfattere og selv naturvidenskabsmand – har skrevet en roman om sorg og ensomhed, om grænserne for vor viden og om de mest grundlæggende spørgsmål: Hvor pålidelig er vores opfattelse af verden? Hvor er genstandene, når vi ikke kan se dem? Hvordan tale om det usigelige?

Quantum Mechanics in Curved Spacetime: A Comprehensive Exploration takes readers on a fascinating journey through the fusion of quantum mechanics and general relativity, unraveling the mysteries of quantum fields in curved geometries, black holes, quantum cosmology, entanglement, and more. This comprehensive guide offers a mathematical framework and explores the cutting-edge research in quantum gravity and the potential applications in quantum technology. Join Kuro Aksara as they navigate the uncharted territory where spacetime and probability blend, providing insights into the fundamental nature of the universe.

Tiden er en gåde. For at løse den tager fysiker Troels Harmark os med på en rejse tilbage til antikkens græske filosoffer, videre op gennem naturvidenskabens historie til bl.a. Newton og Einstein og helt ud til forskningsfronten i moderne fysik og de største spørgsmål som, hvordan universet blev til. Tiden oprandt ved universets fødsel, og vi lever stadig i tiden her 13,8 milliarder år senere. Vi har en krop, der ældes, og kan ikke forestille os vores liv uden tid – vi indordner os under den, og tænker, at den bevæger sig regelmæssigt, som visernes præcise vandring over døgnets timer på uret. Men fysikken beretter en anden historie – om tidens relativitet: at den går langsommere tæt ved Jordens overflade end på toppen af et bjerg, at tiden står stille på kanten af sorte huller, og at universet udvider sig uendeligt. Tidens gang skal findes imellem de to modpoler: at alt er tilfældigt og at alt er uafvendeligt. På sporet af tidens gåde handler om, hvordan det hele hænger sammen, og hvordan det kan være, at man regner med, at tiden en dag vil stoppe med at gå. Hvordan skal vi forstå tiden?

Time, space and entanglement are the main characters in this book. Their nature is still a great mystery in physics and we study here the possibility that these three phenomena are closely connected, showing how entanglement can be at the basis of the emergence of time and space within closed quantum systems. We revisit and extend the Page and Wootters theory that was originally introduced in order to describe the emergence of time through entanglement between subsystems in a globally static, quantum Universe. In the book, after providing a complete review of the salient aspects of the theory, we establish a connection with recent research on the foundations of statistical mechanics and we provide a new understanding of the thermalization process. Furthermore, we generalize the framework in order describe the spatial degree of freedom and we provide a model of 3+1 dimensional, quantum spacetime emerging from entanglement among different subsystems in a globally "timeless" and "positionless" Universe. Finally, via the Page and Wootters theory, the evolution of quantum clocks within a gravitational field is treated and a time dilation effect is obtained in agreement with the Schwarzschild solution.

This Book is the first volume of the series "The Alethiology Proper".The Alethiology Proper is a new and independent discipline of Study (Science) which is a pure logical study of the nature of Reality and Truth.Etymologically "The Alethiology Proper" is defined as the "the Science of Truth Proper". In this study, Reality and Truth are taken as dual realities of the Same. Therefore, "The Alethiology Proper" can also be defined as "the Science of Reality Proper".This Study of Alethiology Proper has its unique methodology of study which has enabled to explore the ultimate answers of the Universe. Through this Study we can explore the Beginning and End of the Universe with absolute certainty. This Study has access even to Nothing and shows with absolute certainty what Nothing is and how Something came out of Nothing.Until now there were many unanswered questions about the Origin of Universe, Existence of God, Origin of Life etc. There are many conflicting theories, ideas, philosophies regarding the Truth of Everything due to the absence of Certainty of the Truth. This Study answers the questions of Origin of Universe, God, Life, Reality and Truth with absolute certainty.This study has bridged the two extremes (though in actuality are not) of Reality, namely Science and Religion, Physical and Spiritual, Seen and Unseen. Therefore, both realities can now be scientifically studied and confirmed with absolute certainty. This Study has independently explored the Reality and have come up with the answer that there is indeed God, a Triune Eternal Living Being.Before I say anything further, I would like to give assurance that this study is purely scientific which is purely objective in nature, therefore, all the ideas of this book could be experimentally verified with absolute certainty. This is not a mere philosophical book filled with subjective opinions or interpretations, but this is a purely objective and scientific study. If the ideas of this book are not equivalent in certainty as the Truth 2+2=4 is, then it may be considered as a fictional work.

This book provides a captivating journey through the realms of classical and quantum systems as it unravels the profound influence that noise may have on their static and dynamic properties. The first part of the book offers succinct yet enlightening discussions on foundational topics related to noise. The second part focuses on a variety of applications, where a diverse spectrum of noise effects in physical systems comes to life, meticulously presented and thoughtfully analyzed. Whether you are a curious student or a dedicated researcher, this book is your key to gaining invaluable insights into noise effects in physical systems. ¿The book has the merit of presenting several topics scattered in the literature and could become a very useful reference.¿ Giovanni Jona-Lasinio, Sapienza ¿ Università di Roma, Italy

The author offers an introduction to the multiverse hypothesis and the current theories attempting to challenge it. This serves as the foundation for addressing the question posed in the title, "Is There a Replica of Me in an Alternate Universe?". Additionally, the author presents a fresh hypothesis, grounded in established and verified quantum theory, with the aim of disproving the notion that an identical version of ourselves exists in an alternate universe.

This volume commemorates the scientific contributions of Detlef Dürr (1951¿2021) to foundational questions of physics. It presents new contributions from his former students, collaborators, and colleagues about their current research on topics inspired or influenced by Dürr. These topics are drawn from physics, mathematics, and philosophy of nature, and concern interpretations of quantum theory, new developments of Bohmian mechanics, the role of typicality, quantum physics in relativistic space-time, classical and quantum electrodynamics, and statistical mechanics. The volume thus also gives a snapshot of present research in the foundations of physics.

"Modern physics is dazzling. What is it about space that will not let an object move faster than light? Why does mass increase and time slow at extremely high velocities? Why is it impossible to know where a particle is if its momentum is known? In everyday experience, why do we feel acceleration but not velocity? These physical phenomena are well known, and their effects are easily calculated, but the dazzle remains. Why do they happen at extreme dimensions -- the very fast, the very small, the very massive, the very distant? The key revolves around the role of the observer, or, in other words, consciousness. Without an observer, the existence of an object itself becomes problematic. It is time to look again at what dimensions are and how they relate to consciousness"--

A guide to connecting with the nine dimensions of consciousness

This brief offers an introduction to the fascinating new field of quantitative read-across structure-activity relationships (q-RASAR) as a cheminformatics modeling approach in the background of quantitative structure-activity relationships (QSAR) and read-across (RA) as data gap-filling methods. It discusses the genesis and model development of q-RASAR models demonstrating practical examples. It also showcases successful case studies on the application of q-RASAR modeling in medicinal chemistry, predictive toxicology, and materials sciences. The book also includes the tools used for q-RASAR model development for new users. It is a valuable resource for researchers and students interested in grasping the development algorithm of q-RASAR models and their application within specific research domains.

Der heutigen Naturphilosophie kommen in der Naturwissenschaft folgende drei Funktionen zu: die Herausarbeitung der grundlegenden Aussagen der wissenschaftlichen Theorien, ihre realistische Deutung innerhalb eines Weltbildes und die Bereitstellung von naturphilosophischen Leitideen zur Anregung der einzelwissenschaftlichen Forschung. Im ersten Teil des Buches wird die heutige methodologische und erkenntnistheoretische Situation der Naturwissenschaft analysiert. In Teil II werden die grundlegenden Phänomene und mathematischen Strukturen der wichtigsten physikalischen Theorie unserer Zeit, der Quantenmechanik, dargestellt und die Welt mit einem Computer verglichen, um damit die mathematischen Formalismen der theoretischen Physik semantisch zu deuten. Die mathematischen Strukturen der physikalischen Theorien besitzen danach eine wirkliche Existenzweise, insofern sie als Software in der Wirklichkeit, im Quantenvakuum, implementiert sind, und beobachtete Objekte sind Abbildungen auf dem Bildschirm bzw. auf den Bildschirmen des Weltcomputers, d.h. Projektionen in die Raumzeit. In Teil III werden aus dem Computer-Weltbild Anregungen für künftige wissenschaftliche Forschungen hergeleitet. Kernstücke bilden hierbei Überlegungen zum Leib-Seele-Problem und zum Funktionalismus der Biologie.

This book provides an alternative approach to time-independent perturbation theory in non-relativistic quantum mechanics. It allows easy application to any initial condition because it is based on an approximation to the evolution operator and may also be used on unitary evolution operators for the unperturbed Hamiltonian in the case where the eigenvalues cannot be found. This flexibility sets it apart from conventional perturbation theory. The matrix perturbation method also gives new theoretical insights; for example, it provides corrections to the energy and wave function in one operation. Another notable highlight is the facility to readily derive a general expression for the normalization constant at m-th order, a significant difference between the approach within and those already in the literature. Another unique aspect of the matrix perturbation method is that it can be extended directly to the Lindblad master equation. The first and second-order corrections are obtained for this equation and the method is generalized for higher orders. An alternative form of the Dyson series, in matrix form instead of integral form, is also obtained. Throughout the book, several benchmark examples and practical applications underscore the potential, accuracy and good performance of this novel approach. Moreover, the method's applicability extends to some specific time-dependent Hamiltonians. This book represents a valuable addition to the literature on perturbation theory in quantum mechanics and is accessible to students and researchers alike.

"This concise textbook introduces an innovative computational approach to quantum mechanics. Emphasizing learning through implementation and simulation of quantum phenomena, it's packed with exercises and examples. Source code and data files are provided, along with solutions. Extra problems with locked solutions are provided online for instructors"--

Characterizing entanglement is an important issue in quantum information, as it is considered to be a resource for many applications such as quantum key distribution or quantum metrology. One useful tool to detect and quantify entanglement are witness operators. A standard way to construct them is based on the fidelity of pure states and mathematically relies on the Schmidt decomposition of vectors. In this book a method to build entanglement witnesses using the Schmidt decomposition of operators is presented. One can show that these are strictly stronger than the fidelity witnesses. Moreover, the concept can be generalized easily to the multipartite case, and one may use it to quantify the dimensionality of entanglement. Finally, this scheme will be used to provide two algorithms that can be combined to improve given witnesses for multiparticle entanglement.

This book presents a new way of thinking about quantum mechanics and machine learning by merging the two. Quantum mechanics and machine learning may seem theoretically disparate, but their link becomes clear through the density matrix operator which can be readily approximated by neural network models, permitting a formulation of quantum physics in which physical observables can be computed via neural networks. As well as demonstrating the natural affinity of quantum physics and machine learning, this viewpoint opens rich possibilities in terms of computation, efficient hardware, and scalability. One can also obtain trainable models to optimize applications and fine-tune theories, such as approximation of the ground state in many body systems, and boosting quantum circuits¿ performance. The book begins with the introduction of programming tools and basic concepts of machine learning, with necessary background material from quantum mechanics and quantum information also provided. This enables the basic building blocks, neural network models for vacuum states, to be introduced. The highlights that follow include: non-classical state representations, with squeezers and beam splitters used to implement the primary layers for quantum computing; boson sampling with neural network models; an overview of available quantum computing platforms, their models, and their programming; and neural network models as a variational ansatz for many-body Hamiltonian ground states with applications to Ising machines and solitons. The book emphasizes coding, with many open source examples in Python and TensorFlow, while MATLAB and Mathematica routines clarify and validate proofs. This book is essential reading for graduate students and researchers who want to develop both the requisite physics and coding knowledge to understand the rich interplay of quantum mechanics and machine learning.

This book bridges the gap between physical foundations and medical applications of the NMR and MRI technologies, making them accessible to both physicists and biomedical scientists. The physical basis of these technologies is discussed in a manner that can be easily understood by scientists from different backgrounds, aiding them in gaining a clearer understanding of the subject.. For instance, the medical applications of NMR and MRI technologies are described in a way that is accessible to physicists. Moreover, geometrical descriptions and specific mathematical tools are used to facilitate the visualizations of many concepts. Furthermore, the book covers modern technologies such as hyperpolarization and several other state-of-the-art techniques, along with their foundations.

Sind Sie fasziniert von den Fragen der Quantenphysik und wollen Sie Beiträge in den Medien zum Thema besser verstehen können? Wolfgang Osterhage gibt Ihnen in diesem kompakten Buch den Einstieg und Überblick, den Sie dafür brauchen - auch ohne quantenphysikalisches Vorwissen! Dieses Buch lädt Sie ein, mitzudenken, und die großen Probleme der Physik des Kleinsten kennenzulernen.Eine Reise durch die Quantenphysik ist und bleibt spannend: denn obwohl die Theorie fast 85 Jahre alt und eine der erfolgreichsten Theorien der Physik ist - hat sie doch viele ihrer Grundsatzfragen bis heute nicht endgültig beantworten können. Es scheint, als habe Richard Feynmanns Ausspruch ¿Ich glaube mit Sicherheit behaupten zu können, daß niemand die Quantenmechanik versteht¿ noch immer Bestand.Um Ihnen den Einstieg zu erleichtern, beginnt dieses Buch mit der Gedankenwelt der Quantenphysik, die manchmal quer zu den Erfahrungen der Alltagswirklichkeit zu stehen scheint. Über das Phänomen der Strahlung wird anschließend atom- und kernphysikalisches Grundwissen vermittelt, bevor es hineingeht in die fremde Welt der Operatoren, Wahrscheinlichkeiten und des Messproblems. Zuletzt münden alle Puzzelstücke in das Standardmodell der Elementarteilchen und in die Quantenfeldtheorie.In der zweiten Auflage wurde das Buch gründlich aktualisiert und u.a. durch die spannenden Themen Quantencomputer und Quanteninformation ergänzt.Eine kurz und bündige Einführung, die Ihnen den Überblick verschafft, den Sie für Ihr Weiterlesen brauchen - viel Freude bei Ihrem Studium Generale.

This book celebrates the life and work of the late Giovanni Morchio (1944¿2021). It features scientific and anecdotal contributions written by his former colleagues, co-authors, and students, as well as senior scientists who were active witnesses to the dramatic advances in physics and in mathematics that took place during his 50-year-long career. The volume begins with a biographical introduction, detailing Giovanni Morchiös life and his role as a physicist, mathematician, teacher, and scientist. The core of the book covers a vast spectrum of ideas, reflecting Dr Morchiös scientific interests. Each chapter develops a specific topic of modern research, ranging from quantum mechanics and quantum field theory to additional themes such as the connection between general relativity and Newtonian gravitation. Every contribution provides a historical retrospective, a survey of advances, an outlook of future perspectives and challenges, and an updated bibliography. The last part collects the authors¿ recollections of their professional and personal interactions with Dr Morchio, in recognition of his deep achievements, his exceptional pedagogical qualities, and his praiseworthy social and pro bono commitment. Authored by physicists of international calibre covering a broad range of subjects, the book will be a valuable reference for researchers and students of theoretical and mathematical physics.

In the mid-19th century, the scientific community was convinced that physics had been fully discovered and only isolated, peripheral issues remained unexplained. One of these was black body radiation (CDC) and the transformation of electromagnetic waves. In 1893, Wien proved that the wavelength at which CDC radiates the greatest amount of energy is inversely proportional to body temperature. Surprisingly, the formula resulting from current, reliable physics describes CDC radiation very well only at low frequencies. For ultraviolet frequencies, the obtained function was constantly upwards. Planck proposed the distribution of the CDC radiation spectrum, assuming that the radiation can only be emitted in precisely defined portions known as quanta. This was the year of the creation of quantum physics, one of the foundations of modern physics. Aristotle recognized that there is a distinctive frame of reference. This view was challenged by Galileo, who concluded that the speed and position of the body are relative. The Galilean transformation became the foundation of Newtonian physics. However, Maxwell¿s equations describing electromagnetic waves were not subject to the Galilean transformation but rather to the Lorentz transformation. The biggest problem at the beginning of the 20th century was the incompatibility of the laws of dynamics and electromagnetism. The theory of relativity is another foundation of modern physics. The last year of the 19th century debunked the myth of full understanding of the laws of nature. It quickly turned out that the knowledge about the universe at that time was very little. This lack of knowledge led to a rapid reconstruction of physics in the first half of the 20th century. is book discusses some of these subjects, including spinor fields, 5D relativity, dissipative quantum system and energy balance, centrifugal acceleration in relativistic astrophysics, and time-dependent photoluminescence.