THE amiable insistence of my friend André George has induced me to collect in the present Volume a number of Studies on contemporary Physics written from both the general and the more metaphysical point of view. Each of these Studies forms an independent whole, and can be read by itself. A slight degree of repetition—which the reader is asked to overlook—has been the inevitable result: for on more than one occasion I have been compelled to duplicate a summary of the great fundamental stages of contemporary Physics, such as the classification of simple substances, the investigation of the photo-electric effect and the origin of the Theory of Light Quanta and of Wave Mechanics: the subjects are somewhat technical, and I cannot well assume that they are common knowledge. But though the same subject is outlined in several of these Studies, I have tried to take up a different point of view in each, and have endeavoured to throw light on different aspects of the essential problems of Quantum Physics in order to facilitate a grasp of their importance. On comparing the different chapters the reader will observe that, while overlapping, they also complement one another; and he will feel the fascination and greatness inherent in the vast structure of modern Physics. And while admiring the vast number and the extreme delicacy of experimental facts which laboratory physicists have succeeded in revealing, and the strange and brilliant concepts devised by theorists to explain them, he will appreciate to what a degree the methods and ideas of physicists have grown in subtlety during recent years, and how great has been the progress from the somewhat ingenuous Realism and the over-simplified Mechanics of earlier thinkers. The more deeply we descend into the minutest structures of Matter, the more clearly we see that the concepts evolved by the mind in the course of everyday experience—especially those of Time and Space—must fail us in an endeavour to describe the new worlds which we are entering. One feels tempted to say that the outlines of our concepts must undergo a progressive blurring, in order that they may retain some semblance of relevance to the realities of the subatomic scales. Time and Space, in other words, are too loose a dress for the elementary entities; individuality becomes attenuated in the mysterious processes of interaction, and even Determinism, the darling of an older generation of physicists, is forced to yield. But the great book of Science is never finished: other surprises await us: who knows what mysteries are hidden within the nucleus of an atom, which, although a million million times smaller than the smallest living thing, is yet a universe in itself?

This compact but exhaustive textbook, now in its significantly revised and expanded second edition, provides an essential introduction to the field quantization of light and matter with applications to atomic physics and strongly correlated systems. Following an initial review of the origins of special relativity and quantum mechanics, individual chapters are devoted to the second quantization of the electromagnetic field and the consequences of light field quantization for the description of electromagnetic transitions. The spin of the electron is then analyzed, with particular attention to its derivation from the Dirac equation. Subsequent topics include the effects of external electric and magnetic fields on the atomic spectra and the properties of systems composed of many interacting identical particles. The book also provides a detailed explanation of the second quantization of the non-relativistic matter field, i.e., the Schrödinger field, which offers a powerful tool for the investigation of many-body problems, and of atomic quantum optics and entanglement. Finally, two new chapters introduce the finite-temperature functional integration of bosonic and fermionic fields for the study of macroscopic quantum phenomena: superfluidity and superconductivity. Several solved problems are included at the end of each chapter, helping readers put into practice all that they have learned.

'Particle or Wave' explains the origins and development of modern physical concepts about matter and the controversies surrounding them.

The book gives an introduction to the field quantization (second quantization) of light and matter with applications to atomic physics. The first chapter briefly reviews the origins of special relativity and quantum mechanics and the basic notions of quantum information theory and quantum statistical mechanics. The second chapter is devoted to the second quantization of the electromagnetic field, while the third chapter shows the consequences of the light field quantization in the description of electromagnetic transitions. In the fourth chapter it is analyzed the spin of the electron, and in particular its derivation from the Dirac equation, while the fifth chapter investigates the effects of external electric and magnetic fields on the atomic spectra (Stark and Zeeman effects). The sixth chapter describes the properties of systems composed by many interacting identical particles by introducing the Hartree-Fock variational method, the density functional theory and the Born-Oppenheimer approximation. Finally, in the seventh chapter it is explained the second quantization of the non-relativistic matter field, i.e. the Schrodinger field, which gives a powerful tool for the investigation of many-body problems and also atomic quantum optics. At the end of each chapter there are several solved problems which can help the students to put into practice the things they learned.

This book draws together the essential elements of classical electrodynamics, surface wave physics, plasmonic materials, and circuit theory of electrical engineering to provide insight into the essential physics of nanoscale light-matter interaction and to provide design methodology for practical nanoscale plasmonic devices. A chapter on classical and quantal radiation also highlights the similarities (and differences) between the classical fields of Maxwell's equations and the wave functions of Schrödinger's equation. The aim of this chapter is to provide a semiclassical picture of atomic absorption and emission of radiation, lending credence and physical plausibility to the "rules" of standard wave-mechanical calculations. The structure of the book is designed around five principal chapters, but many of the chapters have extensive "complements" that either treat important digressions from the main body or penetrate deeper into some fundamental issue. Furthermore, at the end of the book are several appendices to provide readers with a convenient reference for frequently-occurring special functions and explanations of the analytical tools, such as vector calculus and phasors, needed to express important results in electromagnetics and waveguide theory.

Feynman’s bestselling introduction to the mind-blowing physics of QED—presented with humor, not mathematics Celebrated for his brilliantly quirky insights into the physical world, Nobel laureate Richard Feynman also possessed an extraordinary talent for explaining difficult concepts to the public. In this extraordinary book, Feynman provides a lively and accessible introduction to QED, or quantum electrodynamics, an area of quantum field theory that describes the interactions of light with charged particles. Using everyday language, spatial concepts, visualizations, and his renowned Feynman diagrams instead of advanced mathematics, Feynman clearly and humorously communicates the substance and spirit of QED to the nonscientist. With an incisive introduction by A. Zee that places Feynman’s contribution to QED in historical context and highlights Feynman’s uniquely appealing and illuminating style, this Princeton Science Library edition of QED makes Feynman’s legendary talks on quantum electrodynamics available to a new generation of readers.

This book offers a didactic introduction to light–matter interactions at both the classical and semi-classical levels. Pursuing an approach that describes the essential physics behind the functionality of any optical element, it acquaints students with the broad areas of optics and photonics. Its rigorous, bottom-up approach to the subject, using model systems ranging from individual atoms and simple molecules to crystalline and amorphous solids, gradually builds up the reader’s familiarity and confidence with the subject matter. Throughout the book, the detailed mathematical treatment and examples of practical applications are accompanied by problems with worked-out solutions. In short, the book provides the most essential information for any graduate or advanced undergraduate student wishing to begin their course of study in the field of photonics, or to brush up on important concepts prior to an examination.

From the early wave-particle arguments to the mathematical theory of electromagnetism to Einstein's work on the quantization of light, different descriptions of what constitutes light have existed for over 300 years. This book examines the photon phenomenon from several perspectives. It demonstrates the importance of studying the photon as a concept belonging to a global vacuum (matter-free space). The book explains the models and physical and mathematical descriptions of light and examines the behavior of light and its interaction with matter.

Argues that the discoveries of twentieth-century physics--relativity and the quantum theory--demand a radical reformulation of the fundamentals of reality and a way of thinking, that is closer to mysticism than materialism.

World-leading researchers, including Nobel Laureates, explore the most basic questions of science, philosophy, and the nature of existence.