Bøger i Springer Tracts in Modern Physics serien

This book presents a complementary perspective to Schrodinger theory of electrons in an electromagnetic field, one that does not appear in any text on quantum mechanics. The perspective, derived from Schrodinger theory, is that of the individual electron in the sea of electrons via its temporal and stationary-state equations of motion - the 'Quantal Newtonian' Second and First Laws. The Laws are in terms of 'classical' fields experienced by each electron, the sources of the fields being quantum-mechanical expectation values of Hermitian operators taken with respect to the wave function. Each electron experiences the external field, and internal fields representative of properties of the system, and a field descriptive of its response. The energies are obtained in terms of the fields. The 'Quantal Newtonian' Laws lead to physical insights, and new properties of the electronic system are revealed. New mathematical understandings of Schrodinger theory emerge which show the equation to be intrinsically self-consistent.  Another complimentary perspective to Schrdinger theory is its manifestation as a local effective potential theory described via Quantal Density Functional theory. This description too is in terms of 'classical' fields and quantal sources. The theory provides a rigorous physical explanation of the mapping from the interacting system to the local potential theory equivalent.The complementary perspective to stationary ground state Schrdinger theory founded in the theorems of Hohenberg and Kohn, their extension to the presence of a magnetic field and to the temporal domain - Modern Density Functional Theory -- is also described. The new perspectives are elucidated by application to analytically solvable interacting systems. These solutions and other relevant wave function properties are derived.

This book provides a comprehensive introduction to photoelectron angular distributions and their use in the laboratory to study light-matter interactions. Photoelectron angular distribution measurements are useful because they can shed light on atomic and molecular electronic configurations and system dynamics, as well as provide information about quantum transition amplitudes and relative phases that are not obtainable from other types of measurements. For example, recent measurements of molecular-frame photoelectron angular distributions have been used to extract photoelectron emission delays in the attosecond range which can provide ultra-sensitive maps of molecular potentials. Additionally, photoelectron angular distribution measurements are an essential tool for studying negative ions.Here, the author presents a detailed, yet easily accessible, theoretical background necessary for experimentalists performing photoelectron angular distribution measurements to better understand their results. The various physical influences on photoelectron angular distributions are revealed through analytical models with the use of angular momentum coupling algebra and spherical tensor operators. The classical and quantum treatments of photoelectron angular distributions are covered clearly and systematically, and the book includes, as well, a chapter on relativistic interactions. Furthermore, the primary methods used to measure photoelectron angular distributions in the laboratory, such as photodetachment electron spectroscopy, velocity-map imaging, and cold target recoil ion momentum spectroscopy, are described. This book features introductory material as well as new insights on the topic, such as the use of angular momentum transfer theory to understand the process of photoelectron detachment in atoms and molecules. Including key derivations, worked examples, and additional exercises for readers to try on their own, this book serves as both a critical guide for young researchers entering the field and as a useful reference for experienced practitioners.

This book provides readers with a detailed overview of second- and third-order nonlinearities in various nanostructures, as well as their potential applications. Interest in the field of nonlinear optics has grown exponentially in recent years and, as a result, there is increasing research on novel nonlinear phenomena and the development of nonlinear photonic devices. Thus, such a book serves as a comprehensive guide for researchers in the field and those seeking to become familiar with it.This text focuses on the nonlinear properties of nanostructured systems that arise as a result of optical wave mixing. The authors present a review of nonlinear optical processes on the nanoscale and provide theoretical descriptions for second and third-order optical nonlinearities in nanostructures such as carbon allotropes, metallic nanostructures, semiconductors, nanocrystals, and complex geometries. Here, the characterization and potential applications of these nanomaterials are also discussed. The factors that determine the nonlinear susceptibility in these systems are identified as well as the influence of physical mechanisms emerging from resonance and off-resonance excitations. In addition, the authors detail the effects driven by important phenomena such as quantum confinement, localized surface plasmon resonance, Fano resonances, bound states, and the Purcell effect on specific nanostructured systems. Readers are provided with a groundwork for future research as well as new perspectives in this growing field.

This book gives a comprehensive account of modern x-ray science, based on the use of synchrotron radiation and x-ray-free electron lasers (XFELs). It emphasizes the new capabilities of XFELs which extend the study of matter to the intrinsic timescales associated with the motion of atoms and chemical transformations and give birth to the new field of non-linear x-ray science. Starting with the historical understanding of the puzzling nature of light, it covers the modern description of the creation, properties, and detection of x-rays within quantum optics. It then presents the formulation of the interactions of x-rays with atomic matter, both, from semi-classical and first-principles quantum points of view. The fundamental x-ray processes and techniques, absorption, emission, Thomson, and resonant scattering (REXS and RIXS) are reviewed with emphasis on simple intuitive pictures that are illustrated by experimental results. Concepts of x-ray imaging and diffractive imaging of atomic and nano structures are discussed, and the quantum optics formulation of diffraction is presented that reveals the remarkable quantum substructure of light. The unique power of x-rays in providing atom and chemical-bond specific information and separating charge and spin phenomena through x-ray polarization (dichroism) effects are highlighted. The book concludes with the discussion of many-photon or non-linear x-ray phenomena encountered with XFELs, such as stimulated emission and x-ray transparency.

This book comprehensively presents an unconventional quantum criticality caused by valence fluctuations, which offers theoretical understanding of unconventional Fermi-liquid properties in cerium- and ytterbium-based heavy fermion metals including CeCu2(Si,Ge)2 and CeRhIn5 under pressure, and quasicrystal ¿-YbAlB4 and Yb15Al34Au51. The book begins with an introduction to fundamental concepts for heavy fermion systems, valence fluctuation, and quantum phase transition, including self-consistent renormalization group theory. A subsequent chapter is devoted to a comprehensive description of the theory of the unconventional quantum criticality based on a valence transition, featuring explicit temperature dependence of various physical quantities, which allows for comparisons to relevant experiments. Lastly, it discusses how ubiquitous the valence fluctuation is, presenting candidate materials not only in heavy fermions, but also in strongly correlated electrons represented by high-Tc superconductor cuprates. Introductory chapters provide useful materials for learning fundamentals of heavy fermion systems and their theory. Further, experimental topics relevant to valence fluctuations are valuable resources for those who are new to the field to easily catch up with experimental background and facts.