Kvantefysik (kvantemekanik og kvantefeltteori)

‘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.

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.

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 ").

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.

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.

This book provides readers with the current state-of-the-art research and technology on quantum computing. The authors provide design paradigms of quantum computing. Topics covered include multi-programming mechanisms on near-term quantum computing, Lagrange interpolation approach for the general parameter-shift rule, architecture-aware decomposition of quantum circuits, software for massively parallel quantum computing, machine learning in quantum annealing processors, quantum annealing for real-world machine learning applications, queuing theory models for (Fault-Tolerant) quantum circuits, machine learning for quantum circuit reliability assessment, and side-channel leakage in Suzuki stack circuits.

For 100 years, most physicists have believed that it is no longer possible to understand the true constitution of nature. This is due to the unresolved wave-particle paradox, the apparent contradiction between wholeness and divisibility - that subtle smile of Nature that seemed so confusing that theoretical physics threw in the towel in despair as early as 1927. This was a direct consequence of the Copenhagen Interpretation, in which Niels Bohr had postulated an insurmountable barrier of cognition (at least for physicists). Since then, the constitution of nature has been regarded as bizarre and weird, the quantum puzzle as unsolvable and the theory as so complicated that it can no longer be understood by mere mortals.In reality, however, the underlying experiments are of a poignant simplicity that even laymen can easily understand: They show holistic division and branching processes and thus refute the atomic and elementary particle hypothesis, i.e. the hypothesis of indivisibility on which the atomic world view is based. This is precisely the fundamental natural philosophical problem of quantum physics: although the experiment clearly proves that the 2400-year-old Greek idea of the existence of "atoms" - i.e. indivisible particles - cannot apply to nature and reality, we have not yet been able to understand the failure of the atom hypothesis and replace it with a fundamentally new principle of the nature of matter and light.Volume 1 introduces the quantum puzzle and identifies the four cognitive problems of quantum physics. They are obviously caused by assumptions that are considered proven, but must nevertheless be false. So we embark on a detective search for clues in the history of ideas in 19th century physics. The investigation reveals, among other things, that the indivisibility hypothesis already failed experimentally justified in the founding days of chemistry, which led Avogadro to the hypothesis of divisible 'atoms', called molecules. The mechanistic interpretation of this divisibility then led to the salvation of the atomic hypothesis, which, however, around 1927 - in quantum physics - suddenly proved to be untenable. No physicist could make sense of it, which led to a hundred-year blockade of thought in theoretical physics: The atom hypothesis had become a paradigm that apparently could no longer be reasonably questioned...

This book describes the invariant nature of the relativistic quantum field theories utilizing the idea of interpolating the instant form dynamics and the light-front dynamics. While the light-front dynamics (LFD) based on the light-front time was proposed by Dirac in 1949, there has not yet been a salient review on the connection between the LFD and the instant form dynamics (IFD) based on the ordinary time. By reviewing the connection between LFD and IFD using the idea of interpolating the two different forms of the relativistic dynamics, one can learn the distinguished features of each form and how one may utilize those distinguished features in solving the complicated relativistic quantum field theoretic problems more effectively. With the ongoing 12-GeV Jefferson Lab experiments, the internal structures of the nucleon and nuclei are vigorously investigated in particular using the physical observables defined in the LFD rather than in the IFD. This book offers a clear demonstration on why and how the LFD is more advantageous than the IFD for the study of hadron physics, illustrating the differences and similarities between these two distinguished forms of the dynamics. It aims at presenting the basic first-hand knowledge of the relativistic quantum field theories, describing why and how the different forms of dynamics (e.g., IFD and LFD) can emerge in them, connecting the IFD and the LFD using the idea of the interpolation, and demonstrating explicit examples of the interpolation in quantum electrodynamics and other field theories. While the level of presentation is planned mainly for the advanced undergraduate students and the beginning graduate students, the topics of the interpolation between the IFD and the LFD are innovative enough for even the experts in the field to appreciate its usefulness.

This open access book gives a systematic introduction into the spectral theory of differential operators on metric graphs. Main focus is on the fundamental relations between the spectrum and the geometry of the underlying graph.The book has two central themes: the trace formula and inverse problems.The trace formula is relating the spectrum to the set of periodic orbits and is comparable to the celebrated Selberg and Chazarain-Duistermaat-Guillemin-Melrose trace formulas. Unexpectedly this formula allows one to construct non-trivial crystalline measures and Fourier quasicrystals solving one of the long-standing problems in Fourier analysis. The remarkable story of this mathematical odyssey is presented in the first part of the book.To solve the inverse problem for Schrödinger operators on metric graphs the magnetic boundary control method is introduced. Spectral data depending on the magnetic flux allow one to solve the inverse problem in full generality, this means to reconstruct not only the potential on a given graph, but also the underlying graph itself and the vertex conditions.The book provides an excellent example of recent studies where the interplay between different fields like operator theory, algebraic geometry and number theory, leads to unexpected and sound mathematical results. The book is thought as a graduate course book where every chapter is suitable for a separate lecture and includes problems for home studies. Numerous illuminating examples make it easier to understand new concepts and develop the necessary intuition for further studies.

This helpful and pedagogical book offers problems and solutions in quantum mechanics from areas of current research, rarely addressed in introductory courses or textbooks. It is based on the authors' own experience of teaching undergraduate and graduate courses in quantum mechanics, and adapts problems from contemporary research publications to be accessible to students. Each section introduces key quantum mechanical concepts, which are followed by exercises that grow progressively more challenging throughout the chapter. The step-by-step solutions provide detailed mathematical derivations, and explore their application to wider research topics. This is an indispensable resource for undergraduate and graduate students alike, expanding the range of topics usually covered in the classroom, as well as for instructors and early-career researchers in quantum mechanics, quantum computation and communication, and quantum information.

Quantum mechanics is a very successful theory which precisely describes the behavior of microscopic particles. Although the theory provides counter-intuitive predictions, such as that an object can be at two different positions at the same time and the "spooky action at a distance" between two objects, it describes the microscopic world with unprecedental precision. These counter-intuitive quantum behaviors of microscopic particles explainphenomena across disparate scales, from the microscopic scale such as interactions between sub-atomic particles, the atomic spectrum, motion of electrons in solids, and chemical reactions, to macroscopic scale such as behavior of superfluids and superconductors, and even the evolution of stars. So far, no example of conflicts between experiment and theory is known, and the validity of the theory is so broad that one would expect that the quantumtheory can be applied to the macroscopic world, for example, a macroscopic massive object such as a soccer ball can in principle be at two positions at the same time.

This book explores music with respect to quantum computing, a nascent technology that is advancing rapidly. There is a long history of research into using computers for music since the 1950s.Nowadays, computers are essential for the music economy. Therefore, it is very likely that quantum computers will impact the music industry in the time to come.  Consequently, a new area of research and development is emerging: Quantum Computer Music.This unprecedented book presents the new field of Quantum Computer Music. It introduces the fundamentals of quantum computing for musicians and the latest developments by pioneering practitioners.

The clash between Albert Einstein and Niels Bohr in the realm of quantum physics is a legendary and intellectually gripping showdown that has left an indelible mark on the history of science. "Einstein vs. Bohr: Quantum Clash" delves into this epic scientific duel that defined an era and illuminated the intricacies of quantum theory and the nature of reality itself.Albert Einstein, renowned for his groundbreaking theories of relativity and his iconic equation E=mc², is often celebrated as one of the greatest scientific minds in history. However, his skepticism towards the emerging field of quantum mechanics was no less significant. He famously declared that "God does not play dice with the universe," reflecting his unease with the inherent probabilistic nature of quantum theory.On the other side of this scientific clash was Niels Bohr, a Danish physicist and one of the principal architects of quantum mechanics. Bohr's work, which included the development of the Bohr model of the atom and the principle of complementarity, represented a paradigm shift in the understanding of the atomic and subatomic world. He passionately defended the probabilistic nature of quantum mechanics and its limitations.The clash between Einstein and Bohr primarily revolved around their differing interpretations of quantum theory. While Einstein adhered to a realist perspective, believing that there must be hidden variables governing quantum phenomena, Bohr defended a more positivist view, emphasizing that the observer and the act of measurement were integral to the outcome.This intellectual confrontation culminated in debates, letters, and countless discussions that exposed the deep-seated philosophical and methodological differences between the two luminaries. Their feud came to symbolize the complexities of quantum physics and its implications for our understanding of reality.The implications of the Einstein-Bohr clash extended far beyond the realm of academia. It raised profound questions about the nature of scientific knowledge, the limits of human understanding, and the interplay between determinism and indeterminism in the universe. It also challenged scientists and philosophers to grapple with the epistemological and metaphysical implications of quantum mechanics.Ultimately, both Einstein and Bohr made monumental contributions to the advancement of quantum physics. Their respective viewpoints enriched the field by providing alternative perspectives and stimulating critical thinking. While they never reached a conclusive agreement, their dialogue profoundly shaped the way scientists and thinkers approach the mysteries of the quantum world."Einstein vs. Bohr: Quantum Clash" is not only a fascinating exploration of the clash between two scientific giants but also an invitation to ponder the fundamental questions about the nature of reality, the limits of human knowledge, and the enduring quest to decipher the enigmatic world of quantum mechanics. It stands as a testament to the power of intellectual debate in the pursuit of scientific truth.

Based on Jost function theory this book presents an approach useful for different types of quantum mechanical problems. These include the description of scattering, bound, and resonant states, in a unified way. The reader finds here all that is known about Jost functions as well as what is needed to fill the gap between the pure mathematical theory and numerical calculations. Some of the topics covered are: quantum resonances, Regge poles, multichannel scattering, Coulomb interaction, Riemann surfaces, multichannel analog of the effective range theory, one- and two-dimensional problems, many-body problems within the hyperspherical approach, just to mention few of them. These topics are relevant in the fields of quantum few-body theory, nuclear reactions, atomic collisions, and low-dimensional semiconductor nanostructures. In light of this, the book is meant for students, who study quantum mechanics, scattering theory, or nuclear reactions at the advanced level as well as for post-graduate students and researchers in the fields of nuclear and atomic physics. Many of the arguments that are traditional for textbooks on quantum mechanics and scattering theory, are covered here in a different way, using the Jost functions. This gives the reader a new insight into the subject, revealing new features of various mathematical objects and quantum phenomena.

This book provides the rigorous mathematical foundations of Quantum Physics, from the operational meaning of the measuring process to the most recent theories for the quantum scale of space-time geometry. Topics like relativistic invariance, quantum systems with finite and infinitely many degrees of freedom, second quantisation, scattering theory, are all presented through the formalism of Operator Algebras for a precise mathematical justification.The book is targeted to graduate students and researchers in the area of theoretical/mathematical physics who want to learn about the mathematical foundations of quantum physics, as well as the mathematics students and researchers in the area of operator algebras/functional analysis who want to dive into some of the applications of the theory to physics. 

This thesis presents the first realization of non-reciprocal energy transfer between two cantilevers by quantum vacuum fluctuations. According to quantum mechanics, vacuum is not empty but full of fluctuations due to zero-point energy. Such quantum vacuum fluctuations can lead to an attractive force between two neutral plates in vacuum ¿ the so-called Casimir effect ¿ which has attracted great attention as macroscopic evidence of quantum electromagnetic fluctuations, and can dominate the interaction between neutral surfaces at small separations. The first experimental demonstration of diode-like energy transport in vacuum reported in this thesis is a breakthrough in Casimir-based devices. It represents an efficient and robust way of regulating phonon transport along one preferable direction in vacuum. In addition, the three-body Casimir effects investigated in this thesis were used to realize a transistor-like three-terminal device with quantum vacuum fluctuations. These two breakthroughs pave the way for exploring and developing advanced Casimir-based devices with potential applications in quantum information science. This thesis also includes a study of the non-contact Casimir friction, which will enrich the understanding of quantum vacuum fluctuations.

This book presents a set of software engineering techniques and tools to improve the productivity and assure the quality in quantum software development. Through the collaboration of the software engineering community with the quantum computing community new architectural paradigms for quantum-enabled computing systems will be anticipated and developed.The book starts with a chapter that introduces the main concepts and general foundations related to quantum computing. This is followed by a number of chapters dealing with the quantum software engineering methods and techniques. Topics like the Talavera Manifesto for quantum software engineering, frameworks for hybrid systems, formal methods for quantum software engineering, quantum software modelling languages, and reengineering for quantum software are covered in this part. A second set of chapters then deals with quantum software environments and tools, detailing platforms like QuantumPath(R), Classiq as well as quantum software frameworks for deep learning. Overall, the book aims at academic researchers and practitioners involved in the creation of quantum information systems and software platforms. It is assumed that readers have a background in traditional software engineering and information systems.

This thesis explores the physics of non-equilibrium quantum dynamics in homogeneous two-dimensional (2D) quantum gases. Ultracold quantum gases driven out of equilibrium have been prominent platforms for studying quantum many-body physics. However, probing non-equilibrium dynamics in conventionally trapped, inhomogeneous atomic quantum gases has been a challenging task because coexisting mass transport and spreading of quantum correlations often complicate experimental analyses. In this work, the author solves this technical hurdle by producing ultracold cesium atoms in a quasi-2D optical box potential. The exquisite optical trap allows one to remove density inhomogeneity in a degenerate quantum gas and control its dimensionality. The author also details the development of a high-resolution, in situ imaging technique to monitor the evolution of collective excitations and quantum transport down to atomic shot-noise, and at the length scale of elementary collective excitations. Meanwhile, tunable Feshbach resonances in ultracold cesium atoms permit precise and dynamical control of interactions with high temporal and even spatial resolutions. By employing these state-of-the-art techniques, the author performed interaction quenches to control the generation and evolution of quasiparticles in quantum gases, presenting the first direct measurement of quantum entanglement between interaction quench generated quasiparticle pairs in an atomic superfluid. Quenching to attractive interactions, this work shows stimulated emission of quasiparticles, leading to amplified density waves and fragmentation, forming 2D matter-wave Townes solitons that were previously considered impossible to form in equilibrium due to their instability. This thesis unveils a set of scale-invariant and universal quench dynamics and provides unprecedented tools to explore quantum entanglement transport in a homogenous quantum gas.

The supreme goal of every theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of simple datum of experience- Albert EinsteinThis theory is made with layman¿s simple mathematical intuition and vivid imagination but not with any method of Physical Science or Astronomy. The Einstein - Schrödinger - Hawking Theory is simplified theory about Quantum Gravity and Cosmology. It is a theory which combines the Standard Model of Particle Physics to Quantum Field Theory and Theory of General Relativity. It is obviously a bold statement!Don¿t fear failure. Not failure but low aim, is the crime. In glorious attempts it is glorious even to fail!- Bruce Lee

Learn to write algorithms and program in the new field of quantum computing. This second edition is updated to equip you with the latest knowledge and tools needed to be a complex problem-solver in this ever-evolving landscape. The book has expanded its coverage of current and future advancements and investments by IT companies in this emerging technology. Most chapters are thoroughly revised to incorporate the latest updates to IBM Quantum's systems and offerings, such as improved algorithms, integrating hardware advancements, software enhancements, bug fixes, and more.Yoüll examine quantum computing in the cloud and run experiments there on a real quantum device. Along the way yoüll cover game theory with the Magic Square, an example of quantum pseudo-telepathy. Yoüll also learn to write code using QISKit, Python SDK, and other APIs such as QASM and execute it against simulators (local or remote) or a real quantum computer. Then peek inside the inner workings of the Bell states for entanglement, Grover¿s algorithm for linear search, Shor¿s algorithm for integer factorization, and other algorithms in the fields of optimization, and more. Finally, yoüll learn the current quantum algorithms for entanglement, random number generation, linear search, integer factorization, and others. By the end of this book, yoüll understand how quantum computing provides massive parallelism and significant computational speedups over classical computersWhat You'll LearnWrite algorithms that provide superior performance over their classical counterpartsCreate a quantum number generator: the quintessential coin flip with a quantum twistExamine the quantum algorithms in use today for random number generation, linear search, and moreDiscover quantum teleportationHandle the counterfeit coin problem, a classic puzzlePut your knowledge to the test with more than 150 practice exercises

With a rare blend of scientific insight and writing as elegant as the theories it so deftly explains, The Elegant Universe remains unrivaled in its clarity and compulsive readability: "a standard that will be hard to beat" (New York Times Book Review). In this new 25th-anniversary edition, renowned physicist and author Brian Greene, "the single best explainer of abstruse concepts in the world today" (Washington Post), updates this classic work with a new preface and epilogue summarizing impactful theoretical and experimental developments over the past quarter-century. From established science, including relativity and quantum mechanics, to the cutting edge of thinking on black holes, string theory, and quantum gravity, The Elegant Universe makes some of the most sophisticated concepts ever contemplated thoroughly accessible and entertaining, bringing us closer than ever to comprehending how the universe works."Few humans share Greene's mastery of the latest cosmological science and English prose."-Dennis Overbye, New York Times

A mesmerizing trip to the strange new world of white holes, from Carlo Rovelli, the bestselling author of Seven Brief Lessons on PhysicsLet us journey into the heart of a black hole. Let us slip beyond its boundary, the horizon, and tumble - on and on - down this crack in the universe. As we plunge, we'll see geometry fold, we'll feel the equations draw tight around us. Eventually, we'll pass it: the remains of a star, deep and dense and falling further far. And then - the bottom. Where time and space end, and the white hole is born . . . With lightness and magic, here Carlo Rovelli traces the ongoing adventure of his own cutting-edge research, of the uncertainty and joy of going where we've not yet been. Guiding us to the edge of theory and experiment, he invites us to go beyond, to experience the fever and the disquiet of science. Here is the extraordinary life of a white hole.

Quantum mechanics is an extraordinarily successful scientific theory. It is also completely baffling. From the moment of its inception, its founders struggled to understand its meaning. This struggle was most famously encapsulated in the debate between Niels Bohr and Albert Einstein; Quantum Drama tells the story of their engagement and its legacy.

Schon früh im Physikstudium und auch bereits in der Schule machen wir Bekanntschaft mit der klassischen Elektrostatik, Magnetostatik, aber auch der Elektrodynamik. Dabei sind die Maxwell-Gleichungen ein nicht mehr wegzudenkender, wichtiger Teil zur Beschreibung des Zusammenhangs zwischen elektrischen und magnetischen Feldern. Doch was ist, wenn wir weiter gehen, wenn wir den klassischen Pfad verlassen und uns der quantenmechanischen Theorie zuwenden? Finden wir dort unsere Wechselwirkung zwischen Licht und Materie wieder? Gibt es, ähnlich wie die Maxwell-Gleichungen, auch solch prägende Gleichungen?Diese Fragen beschäftigen uns in der vorliegenden Arbeit, wobei dazu zunächst die Korrespondenz der relativistischen Mechanik und relativistischen Quantenmechanik untersucht wird. Weiterführend folgt die Quantisierung von Feldern und diese geht in die Quantenelektrodynamik über. Hier werden, aufgrund des einführenden Charakters, nur Prozesse niedrigster Ordnung betrachtet und ein besonderes Augenmerk liegt auf der Compton-Streuung.