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The Problems of Physics

Anthony Leggett

Is the universe infinite, or does it have an edge beyond which there is, quite literally, nothing? Do we live in the only possible universe? Why does it have one time and three space dimensions — or ... More

Is the universe infinite, or does it have an edge beyond which there is, quite literally, nothing? Do we live in the only possible universe? Why does it have one time and three space dimensions — or does it? What is it made of? What does it mean when we hear that a new particle has been discovered? Will quantum mechanics eventually break down and give way to a totally new description of the world, one whose features we cannot even begin to imagine? This book aims to give a general overview of what physicists think they do and do not know in some representative frontier areas of contemporary physics. After sketching out the historical background, the book goes on to discuss the current situation and some of the open problems of cosmology, high-energy physics, and condensed-matter physics. This book focuses not so much on recent achievements as on the fundamental problems at the heart of the subject, and emphasizes the provisional nature of our present understanding of things.Less

Quantum Field Theory of Many-Body Systems: From the Origin of Sound to an Origin of Light and Electrons

Xiao-Gang Wen

For most of the last century, condensed matter physics has been dominated by band theory and Landau's symmetry breaking theory. In the last twenty years, however, there has been an emergence of a new ... More

For most of the last century, condensed matter physics has been dominated by band theory and Landau's symmetry breaking theory. In the last twenty years, however, there has been an emergence of a new paradigm associated with fractionalization, emergent gauge bosons and fermions, topological order, string-net condensation, and long range entanglements. These new physical concepts are so fundamental that they may even influence our understanding of the origin of light and electrons in the universe. This book is a pedagogical and systematic introduction to the new concepts and quantum field theoretical methods in condensed matter physics. It discusses many basic notions in theoretical physics which underlie physical phenomena in nature, including a notion that unifies light and electrons. Topics covered include dissipative quantum systems, boson condensation, symmetry breaking and gapless excitations, phase transitions, Fermi liquids, spin density wave states, Fermi and fractional statistics, quantum Hall effects, topological/quantum order, and spin liquid and string-net condensation. Methods discussed include the path integral, Green's functions, mean-field theory, effective theory, renormalization group, bosonization in one- and higher dimensions, non-linear sigma-model, quantum gauge theory, dualities, projective construction, and exactly soluble models beyond one-dimension.Less

X-Ray Compton Scattering

Malcolm Cooper, Peter Mijnarends, Nobuhiro Shiotani, Nobuhiko Sakai, and Arun Bansil

This book covers all aspects of the study of ground state electron density in condensed matter through Compton scattering of hard x-rays or gamma rays, i.e., photons with energies between 20 and 500 ... More

This book covers all aspects of the study of ground state electron density in condensed matter through Compton scattering of hard x-rays or gamma rays, i.e., photons with energies between 20 and 500 keV. This inelastic scattering process yields information about the momentum distribution of the electrons: it is complementary to x-ray diffraction studies of the position space electron density. After a brief historical introduction, the scattering cross-section is fully elaborated and the approximations within which the experiments can be interpreted are spelled out. All the experimental methods associated with the study of the electron’s momentum density distribution are described and the interpretative techniques are detailed, including the two methods of reconstructing the three-dimensional distribution from the measurement sets. Particular emphasis is placed on the use of synchrotron radiation as the radiation source, especially the use of circularly polarized synchrotron radiation to study the spin-dependent distribution in ferro-magnets. The book concludes with a comparison between Compton scattering methods and a number of allied techniques.Less

The Universe in a Helium Droplet

Grigory E. Volovik

There are fundamental relations between three vast areas of physics: particle physics, cosmology, and condensed matter physics. The fundamental links between the first two areas — in other words, ... More

There are fundamental relations between three vast areas of physics: particle physics, cosmology, and condensed matter physics. The fundamental links between the first two areas — in other words, between micro- and macro-worlds — have been well established. There is a unified system of laws governing the scales from subatomic particles to the cosmos and this principle is widely exploited in the description of the physics of the early universe. This book aims to establish and define the connection of these two fields with condensed matter physics. According to the modern view, elementary particles (electrons, neutrinos, quarks, etc.) are excitations of a more fundamental medium called the quantum vacuum. This is the new ‘aether’ of the 21st century. Electromagnetism, gravity, and the fields transferring weak and strong interactions all represent different types of the collective motion of the quantum vacuum. Among the existing condensed matter systems, a quantum liquid called superfluid 3He-A most closely represents the quantum vacuum. Its quasiparticles are very similar to the elementary particles, while the collective modes are analogues of photons and gravitons. The fundamental laws of physics, such as the laws of relativity (Lorentz invariance) and gauge invariance, arise when the temperature of the quantum liquid decreases.Less

Quantum Theory of Solids

R. E. Peierls

This book develops the quantum theory of solids from the basic principles of quantum mechanics. The emphasis is on a single statement of the ideas underlying the various approximations that have to ... More

This book develops the quantum theory of solids from the basic principles of quantum mechanics. The emphasis is on a single statement of the ideas underlying the various approximations that have to be used in the study of this subject. Care is taken to separate sound arguments from conjecture. The treatment covers the electron theory of metals as well as the dynamics of crystals, including the author's work on the thermal conductivity of crystals.Less

Spin Glasses and Complexity

Daniel L. Stein and Charles M. Newman

Spin glasses are disordered magnetic systems that have led to the development of mathematical tools with an array of real-world applications, from airline scheduling to neural networks. This book ... More

Spin glasses are disordered magnetic systems that have led to the development of mathematical tools with an array of real-world applications, from airline scheduling to neural networks. This book offers the most concise, engaging, and accessible introduction to the subject, fully explaining what spin glasses are, why they are important, and how they are opening up new ways of thinking about complexity. This one-of-a-kind guide to spin glasses begins by explaining the fundamentals of order and symmetry in condensed matter physics and how spin glasses fit into and modify this framework. The book then explores how spin-glass concepts and ideas have found applications in areas as diverse as computational complexity, biological and artificial neural networks, protein folding, immune response maturation, combinatorial optimization, and social network modeling. Providing an essential overview of the history, science, and growing significance of this exciting field, the book also features a forward-looking discussion of what spin glasses may teach us in the future about complex systems. This is a useful book for students and practitioners in the natural and social sciences, with new material even for the experts.Less

Stealing the Gold: A celebration of the pioneering physics of Sam Edwards

David Sherrington

Paul Goldbart and Nigel Goldenfeld (eds)

The collection of trails blazed by Sam Edwards during half a century of fundamental research in theoretical physics is truly astonishing. He led theoretical physics into uncharted territories from ... More

The collection of trails blazed by Sam Edwards during half a century of fundamental research in theoretical physics is truly astonishing. He led theoretical physics into uncharted territories from his roots in quantum field theory — beginning with his seminal work on the transport properties of disordered metals, and continuing to the present day with his ground-breaking efforts to create a statistical mechanics of granular materials. Along the way, he and his collaborators developed the first modern theory of polymers in solution and in the rubbery state; created and explored the tube concept, which has had momentous implications for understanding the viscoelasticity of polymer melts; formulated the spin-glass problem and provided its first solutions using the method of replicas — work that has had profound implications in areas as diverse as combinatorial optimization, neural networks, as well as glassy systems; made important contributions to the still-unsolved problem of Navier-Stokes turbulence; and initiated the recent explosion of activity in the dynamics of growing interfaces. This book celebrates Sam's impact by collecting together and reprinting eleven of his papers, each of which played a seminal role and started a new field of study, each followed by one or more original articles by experts in the relevant fields demonstrating how the topics Sam started have developed to the modern day.Less

Concepts in Thermal Physics

Stephen J. Blundell and Katherine M. Blundell

An understanding of thermal physics is crucial to much of modern physics, chemistry, and engineering. This book provides a modern introduction to the main principles that are foundational to thermal ... More

An understanding of thermal physics is crucial to much of modern physics, chemistry, and engineering. This book provides a modern introduction to the main principles that are foundational to thermal physics, thermodynamics, and statistical mechanics. The key concepts are carefully presented in a clear way, and new ideas are illustrated with worked examples as well as a description of the historical background to their discovery. Applications are presented to subjects as diverse as stellar astrophysics, information and communication theory, condensed matter physics, and climate change. Each chapter concludes with detailed exercises. This second edition of the text maintains the structure and style of the first edition but extends its coverage of thermodynamics and statistical mechanics to include several new topics, including osmosis, diffusion problems, Bayes theorem, radiative transfer, the Ising model, and Monte Carlo methods. New examples and exercises have been added throughout.Less

A Mind Over Matter: Philip Anderson and the Physics of the Very Many

Andrew Zangwill

Philip W. Anderson (1923–2020) is widely regarded as one of the most accomplished and influential physicists of the second half of the twentieth century. Educated at Harvard, he served during World ... More

Philip W. Anderson (1923–2020) is widely regarded as one of the most accomplished and influential physicists of the second half of the twentieth century. Educated at Harvard, he served during World War II as a radar engineer, and began a thirty-five year career at Bell Laboratories in 1949. He was soon recognized as one of the pre-eminent theoretical physicists in the world, specializing in understanding the collective behavior of the vast number of atoms and electrons in a sample of solid matter. He won a one-third share of the 1977 Nobel Prize for Physics for his discovery of a phenomenon common to all waves in disordered matter called Anderson localization and the development of the Anderson impurity model to study magnetism. At Cambridge and Princeton Universities, Anderson led the way in transforming solid-state physics into the deep, subtle, and coherent discipline known today as condensed matter physics. He developed the concepts of broken symmetry and emergence and championed the concept of complexity as an organizing principle to attack difficult problems inside and outside physics. In 1971, Anderson was the first scientist to challenge the claim of high-energy particle physicists that their work was the most deserving of federal funding. Later, he testified before Congress opposing the Superconducting Super Collider particle accelerator. Anderson was a dominant figure in his field for almost fifty years. At an age when most scientists think about retirement, he made a brilliant contribution to many-electron theory and applied it to a novel class of high-temperature superconductors.Less

Helium Three

Roland Dobbs

The condensed phases of helium three provide an exciting laboratory for many fundamental questions in condensed matter physics. Due to its light mass and weak interatomic potential, the condensed ... More

The condensed phases of helium three provide an exciting laboratory for many fundamental questions in condensed matter physics. Due to its light mass and weak interatomic potential, the condensed phases of helium display quantum effects more dramatically than any other atomic system. Intuition based on classical experience is often misleading in these phases: the solid phase for instance is less ordered at low temperature than the liquid phase. The book covers all the low temperature properties of helium three as liquid, superfluid, and solid. It provides an introduction to the extensive literature on helium three from the point of view of an experimentalist, and includes the analogy of its properties with the cosmological ‘big bang’.Less

Quantum Statistical Field Theory: An Introduction to Schwinger's Variational Method with Green's Function Nanoapplications, Graphene and Superconductivity

Norman J. Morgenstern Horing

The methods of coupled quantum field theory, which had great initial success in relativistic elementary particle physics and have subsequently played a major role in the extensive development of ... More

The methods of coupled quantum field theory, which had great initial success in relativistic elementary particle physics and have subsequently played a major role in the extensive development of non-relativistic quantum many-particle theory and condensed matter physics, are at the core of this book. As an introduction to the subject, this presentation is intended to facilitate delivery of the material in an easily digestible form to students at a relatively early stage of their scientific development, specifically advanced undergraduates (rather than second or third year graduate students), who are mathematically strong physics majors. The mechanism to accomplish this is the early introduction of variational calculus with particle sources and the Schwinger Action Principle, accompanied by Green’s functions, and, in addition, a brief derivation of quantum mechanical ensemble theory introducing statistical thermodynamics. Important achievements of the theory in condensed matter and quantum statistical physics are reviewed in detail to help develop research capability. These include the derivation of coupled field Green’s function equations of motion for a model electron-hole-phonon system, extensive discussions of retarded, thermodynamic and non-equilibrium Green’s functions, and their associated spectral representations and approximation procedures. Phenomenology emerging in these discussions includes quantum plasma dynamic, nonlocal screening, plasmons, polaritons, linear electromagnetic response, excitons, polarons, phonons, magnetic Landau quantization, van der Waals interactions, chemisorption, etc. Considerable attention is also given to low-dimensional and nanostructured systems, including quantum wells, wires, dots and superlattices, as well as materials having exceptional conduction properties such as superconductors, superfluids and graphene.Less