bluuebunny/crossref_metadata_2025 huggingface dataset:
Behaviour of the electron beam in a synchrotron radiation storage ring. Energy oscillations
Authors: Duke Philip John
Published: November 2023

Just as deviations form the ideal orbit lead to betatron oscillations, so also deviations from the ideal energy lead to energy oscillations which are sometimes called synchrotron oscillations. These oscillations contribute to the size of the electron beam in the horizontal plane because energy deviations lead to deviations in position and direction of the electrons through the dispersion function fsee eqn ( 11.9)]. Because the dispersion function depends on the value of the s-coordinate around the ring, the contribution of the energy oscillations to beam size also depends on D(s). Furthermore, because the dispersion function tends to follow the contour of the beta function [see eqn ( I 1.11)], the effects of the betatron and synchrotron oscillations tend to combine to increase the beam size instead of cancelling each other out. If the energy distribution of the electrons follows a Gaussian function with standard deviation σ(E), then from eqn (11.9) the contribution of the energy oscillations to the total beam width is (σ (E)/ Eo) × D(s). In any practical storage ring, Q is a long way from resonance so we can assume that the two types of oscillations are uncorrelated and add the contributions from the betatron [eqn ( 10.29)] and synchrotron oscillation in quadrature.
Transverse Beam Dynamics In Circular Particle Accelerators For High Energy Physics
Authors: Asner Fred M
Published: November 2023

Classical and superconducting magnets and conventional and superconductive high frequency cavities are the basic elements in any circular accelerator and collider. The magnets determine the particle or beam behaviour in the transverse plane, the cavities in the longitudinal. Specific beam oscillations, related to the interplay of both transverse and longitudinal phenomena, will not be considered. Since we are mainly interested in the quality and requirements on superconducting accelerator magnets, a short introduction to transverse beam dynamics and beam optics will be given. The success of any accelerator or collider for high energy physics will, among others, depend on a close harmonization and mutual matching between transverse beam dynamics requirements and the superconducting magnet performances from the design stage to the completion and operation of the accelerator.
Perturbation Theory and the WKB Approximation
Authors: Kashiwa T , Ohnuki Y , Suzuki M
Published: November 2023

Path integral formulae for the (p, q) system and (a†, a) of the Bose and Fermi systems can only be calculated exactly in the harmonic oscillator case. Other physical situations require some approximation schemes. In this chapter we try to make explicit calculations for the harmonic oscillator and discuss a perturbation technique and the WKB approximation that is considered to be most suited to the path integral formalism. As an illustrative example, a detailed computation is performed for the case where non-trivial solutions, called instantons, exist in the classical equation of motion.
Problems in Solid State Physics
Authors: Kashiwa T , Ohnuki Y , Suzuki M
Published: November 2023

In the present chapter, we explain some basic applications of the path integral method in condensed matter physics without going into details of calculations, with a great emphasis on the conceptual parts of it. The first example is a theory of stochastic processes in which the path integral is explained physically. Using this, a fundamental mechanism of order formation in an unstable system is discussed. The second topic is to treat a chemical reaction quantum mechanically from the viewpoint of molecular collisions, using the path integral formulation. The third topic is macrscopic tunnelling and its frictional effect.
Properties of an isolated polymer molecule
Authors: Doi M , See H
Published: November 2023

A polymer is a large molecule made up of many small, simple chemical units, joined together by chemical reaction. For example, polyethylene As with most other substances, in order to understand the properties of polymeric materials we must consider a large assembly of molecules. However, in the case of polymers, the molecules themselves are very large, and we need to use statistical mechanics to calculate the characteristics of even an isolated polymer. One way to investigate the properties of a single polymer is to place it in a very dilute solution, so that interactions between the polymers can be neglected. Experimentally, such dilute polymer solutions are used to determine the size and molecular weight of the molecule. In this chapter, we will theoretically investigate the properties of an isolated, single polymer chain in solution.
Concentrated solutions and melts
Authors: Doi M , See H
Published: November 2023

As the concentration in a polymer solution is increased, the molecules start to overlap and begin to entangle with each other as shown in Fig. 2.1. The critical concentration at which this commences is called the overlap concentration. Let us write c* for the number of segments per unit volume at this concentration, so that the number of polymers per unit volume is c* / N.Since the volume of one polymer is of the order R/, we must have Notice that the overlap starts at very low concentration if N is large. (For example, polystyrenes of molecular weight 10 start to overlap at 0.5 % weight concentration.) Therefore, polymers with large molecular weight are almost always in the entangled state, and are strongly interacting with each other.
Quantum Theory
Authors: Araki Huzihiro
Published: November 2023

In this chapter we explain how we can describe quantum theory within the general framework given in Chapter 1. We do not discuss various theories concerning the question of how quantum theory can (or cannot) be deduced from experimental facts or from a verifiable axiomatic system. Instead we start by introducing the assumptions of quantum theory. The main content is the algebraic viewpoint of quantum theory based on the theory of operator algebras, the GNS construction which supplies the fundamental relation between the description of the states by Hilbert space vectors and the description of the states in this general framework, the Wigner theorem which is basic for the mathematical description of quantum mechanical symmetries, and its generalizations. The basic definitions and theorems about Hilbert spaces and operator algebras are collected in the appendix.
Microscopic Experimental Techniques
Authors: Chikazumi Sōshin , Graham, Jr C D
Published: November 2023

As discussed in Chapter 3, atomic magnetic moments originate from orbital or spin magnetic moments of electrons in unclosed electron shells. In addition to these moments, atomic nuclei possess small but non-zero magnetic moments. These moments are measured innuclear magnetons.
Magnetic Disorder
Authors: Chikazumi Sōshin , Graham, Jr C D
Published: November 2023

Diamagnetism means a feeble magnetism, which occurs in a material containing no atomic magnetic moments.
Magnetism Of Ferrimagnetic Oxides
Authors: Chikazumi Sōshin , Graham, Jr C D
Published: November 2023

Most oxides are electrically insulating. Therefore magnetic oxides such as ferrites exhibit very low losses when magnetized in high-frequency fields. This characteristic has been very useful in magnetic materials for communication and information devices. In Section 9.1 we note the general features of oxide crystals, then discuss magnetic and crystalline properties of spinel ferrites in Section 9.2, garnet ferrites in Section 9.3, hexagonal ferrites in Section 9.4, and finally other oxides in Section 9.5.
Magnetism Of Amorphous Materials
Authors: Chikazumi Sōshin , Graham, Jr C D
Published: November 2023

In Chapters 8−10, we treated metals, oxides and compounds, all in crystalline form with atoms arranged on regular lattices. There is another group of materials,amorphous materials,in which the atoms are distributed in an irregular manner. Ordinary glass is a representative example of an amorphous material. When a beam of monochromatic X-rays is scattered by such an amorphous material, there is no well-defined diffraction pattern, as in the case for crystalline materials. Instead there are only diffuse halos, from which we can deduce the statistical distribution of atoms.
Spin Distribution And Domain Walls
Authors: Chikazumi Sōshin , Graham, Jr C D
Published: November 2023

Micromagnetics is the name coined by Brown1,2 for the procedure by which the distribution of spins in a ferromagnet of finite size is solved from first principles. In an infinitely long, thin ferromagnet, the spontaneous magnetization is aligned parallel to the long axis, thus forming a single domain. In a ferromagnet of finite size, such a single domain produces surface free poles which give rise tomagnetostatic energy,Umag In order to reduce Umag, the spin distribution must be altered, which modifies the complete parallel spin alignment. As a result,exchange energy, Uex, magnetoc,ystalline energy, Ua,or Ua magnetoelastic energy, Uλare increased. The stable spin distribution is determined by minimizing the total energy
Fundamental Constants And Energy Conversion Factors
Authors: Taylor Barry N , Cohen E Richard
Published: November 2023

This chapter gives the values of the basic fundamental physical constants and energy conversion factors of physics and chemistry currently recommended for international use by CODATA*. These values, the most up-to-date, self consistent set presently available, are a direct result of the 1986 CODATA least-squares adjustment of the fundamental constants carried out by the authors under the auspices of the CODATA Task Group on Fundamental Constants. The 1986 CODATA set of recommended values replaced the 1973 set, its immediate predecessor, which resulted from the 1973 CODATA least-squares adjustment.3’4 That adjustment was also carried out by the authors under the auspices of the Task Group.
Tables Of Alpha-Particle Emitters: Energies And Emission Probabilities
Authors: Nichols A L
Published: November 2023

A large majority of the alpha-particle-emitting radionuclides are identified with the heavier elements, which are generally more unstable with respect to 4He emissions than the other decay modes. It should be noted that the result¬ing tabulations are not comprehensive; they do not include all known alpha particle-emitting radionuclides nor all of the alpha-particle emissions identified with each individual radionuclide. Only the major alpha-particle emissions are listed (i.e. generally emission probabilities greater than 0.01), along with indications of the commonly used energy and emission probability standards.
Table of Nuclides*
Authors: Tuli† Jagdish K
Published: November 2023

This table presents half-life, abundance, decay modes, spin, parity, and mass excess for all known nuclides and some of their isomeric states. The data given here are from the adopted properties of the various nuclides as given in the Evaluated Nuclear Structure Data File (ENSDF)1. The data in ENSDF are based on experimental results as reported in Nuclear Data Sheets for A=45 to 266 and in Nuclear Physicsfor A<45. For those nuclides for which either there are no data in ENSDF or more recent data are available, the half-life and decay modes are taken from the Chart of the Nuclides, 14th Edition.
Resume of bulk semiconductor physics
Authors: Kelly M J
Published: November 2023

In this chapter, we collect some of the key basic facts about the bulk properties of the semiconductors silicon, gallium arsenide, and aluminium arsenide that form the background material for the rest of this book. The material is selected solely on the basis of its use in subsequent chapters. If this were a book on solid state physics, such as those written by Kittel (1986), Ashcroft and Mermin (1976), or Madelung (1978), or on bulk semiconductors, such as those by Smith (1978), Seeger (1991), or Harrison (1980), much greater detail would be appropriate. We refer readers to these texts in the search of that greater detail. In particular, the terms in italics in this chapter have precise definitions which can be obtained from these texts.
III-V Semiconductor Homojunctions And Heterojunctions
Authors: Kelly M J
Published: November 2023

In the Introduction, we referred to the hundredfold reduction in the lateral feature size of transistors in integrated circuits over the period from the late 1960s to the present day. This reduction has been accompanied by a similar scaling down of vertical dimensions of the devices, i.e. in the thicknesses of the individual layers (see Dennard et al. (1974) and Chapter 21 below). Indeed, if one takes the p-n-p bipolar transistor from its earliest fabrication to the present day, new technologies that have allowed the ever sharper internal interfaces of devices to be achieved have appeared at intervals of approximately 10 years. The original transistors were made in the 1950s by alloying in the species to make a p-type layer in a host n-type material, and then overalloying to produce a new n-type layer near the surface. This technique is exceptionally crude by today’s standards. The interface between then- and p-type material is uncontrolled over thicknesses of micrometres. Furthermore, the interface follows the melt front of the alloying species.
Fabrication Technologies For Semiconductor Microstructu Res
Authors: Kelly M J
Published: November 2023

The last chapter began with a reference to the hundredfold decrease in the key feature sizes of the transistors that appear in memory chips from small fractions of a millimetre in the 1960s to fractions of a micrometre today. In Fig. 3.1, we show a section of part of a Si circuit and a high magnification photograph of the surface. In general, such diagrams and photographs do not do justice to the very tight tolerances that must be achieved before the devices work to full specification, but we should bear them in mind as we proceed. It is not sufficient to produce a small structure as the key part of a device, unless that structure can be repeated millions of times with a spread in properties that is a smaller fraction again of the structure of interest, for example 0.1 µm length gates with rather less than 10 per cent variation in that length. The purpose of this chapter is to describe the technologies used in the fabrication of semiconductor microstructures for physics and device studies. The techniques described here as used for research purposes are recognizable extrapolations of the technologies as used in the manufacture of today’s integrated circuits (whether in Si or GaAs). These state-of-the-art fabrication techniques are available precisely because they are foreseen as essential in one or other strategy for the fabrication of future devices. The physics investigation of these microstructures, quite apart from its intrinsic interest, is meant to shed light on the various choices of technology that might be applied in the year 2000 and beyond.
The two-dimensional electron gas
Authors: Kelly M J
Published: November 2023

In this chapter, we describe the two main systems that have driven research into low-dimensional physics over the last two decades. The metal-oxide-semiconductor field-effect transistor (MOSFET) was patented over 50 years ago, but the technology of oxidizing a Si surface in a way that left few remaining unsatisfied bonds (which have undesirable electrical activity) was perfected only in the 1960s, just in time for its exploitation in modern integrated circuitry where it has been the key active device (Nicollian and Brews 1982). High electron mobilities in GaAs-AlGaAs multilayers with selective doped layers were discovered in 1978 (Dingle et al. 1978), and this selective doping principle has become incorporated into the high-electronmobility transistor (HEMT), at present the lowest noise transistor available, and used in amplifying weak signals, with the particular domestic application of receiving television signals from space. The commercial success of these two structures has increased the levels of research investment in multilayer structures more generally. In both structures, we have electrons that are ‘trapped’ at an interface, but are free to move (with metallic-like conduction properties) along the interface. The physics of these electron systems has been of wide interest, while attempts to improve the performance of these structures as devices have led to many of the new materials and device technologies that we now take for granted. Historically, the Si-Si02 system dominated research in the 1970s (Ando et al. 1982), while the GaAs-AlGaAs heterojunction dominated research in the 1980s. Although most of this book is about III-V epitaxial multilayers, experience with the Si MOSFET set the scene for much of the research that followed.
Quantum pillars and boxes: electronic and optical properties
Authors: Kelly M J
Published: November 2023

New physics associated with hot electron injection, tunnelling, and quantum confinement is made possible with hetero junctions in multilayer semiconductor structures. The new physics has been successfully applied to devices, where the hetero junctions ensure that the active volume is Q2D (as in FETs and quantum-well lasers). Even the tunnel structures are very thin in one of the three spatial dimensions. Given the proven advantages in going from bulk to Q2D systems, a further reduction in dimensionality might again lead to new and exploitable physics in semiconductors. We describe the new physics in this chapter and comment on its exploitability. We concentrate on the fabrication of structures that are on the quantum-length scale of c.20 nm in two, or all three, spatial dimensions, giving quantum wires (pillars) and quantum dots (boxes) respectively. We concentrate on the electrical and optical properties of the former and the optical properties of the latter. In practice, we encounter some new effects associated with the intrinsically small size of the structures (i.e. containing only a few carriers), but we leave the general physics of such mesoscopic systems to the following chapter. In addition, the finite charge of an electron plays a role in the energetics of small structures, and effects associated with this are also treated in Chapter 12.
Exotic materials combinations: new physics including strain
Authors: Kelly M J
Published: November 2023

So far, we have considered the physics of the GaAs-AlxGa1-x  As system. The alloy semiconductor is direct gap for Al contents below 45 per cent, and the effective mass approximation gives a satisfactory (semi-quantitative) account of all the important optical and electronic properties of multilayers and microstructures. For more than 45 per cent Al, the wider-gap material is indirect gap and some further care must be taken with the detailed matching of wave functions at the interfaces if quantitative results are sought. The GaAs-AIGaAs materials system is the most mature, as the lattice constant varies by less than 0.2 per cent across the entire composition range. Furthermore, the thermal expansion of the alloy and GaAs are the same, so that no further stresses are introduced as the material is cooled to room temperature and further to cryogenic temperatures from typical multilayer growth temperatures of about 580-600 °C. Even within this fairly straightforward system, the precise offset of the conduction and valence bands at the abrupt heterojunction has been a matter of continuing debate. It is now thought that a conduction band to valence band offset ratio of 65 ±5 per cent to 35 ±5 per cent is appropriate for describing the physics of the hetero junctions. However, abrupt doping profiles similar those of the planar doped barrier described in Chapter 2, Section 2.6, can introduce (deliberately or unintentionally) a dipole layer at a heterojunction, and so move the two band structures with respect to each other in energy (Shen et al. 1992).
Amorphous semiconductor multilayers
Authors: Kelly M J
Published: November 2023

So far, all the materials physics and devices have used single-crystal multilayer semiconductor structures. Great effort has been made in the growth to achieve precise single-crystal properties and sharp interfaces between adjacent layers. During the fabrication of devices, the process steps attempt to preserve the crystalline integrity. In the past 20 years, hydrogenated amorphous Si has developed rapidly from a research material (first doped to make p-n junction devices in 1976) to the host material for the electronics of displays, with a $4 billion turnover in 1991-1992 (Le Comber 1992). It is now possible to obtain photocells for powering calculators, watches, etc., photoconductors for a wide range of sensing applications, thin-film transistors for driving liquid-crystal displays, and high-voltage thin-film transistors for driving printers. The films of amorphous Si suitable for devices are prepared by plasma-enhanced chemical vapour deposition from SiH4. In the early days, the role of hydrogen was underestimated in this device-grade material, but it is now known to constitute anywhere in the 2-16 at. % range (Street 1991) (this reference is a comprehensive introduction to hydrogenated amorphous Si, including an introduction to multilayers). The role of hydrogen is to saturate all the unsatisfied dangling bonds in a continuous random network. Studies of ideal random networks (shown schematically in Fig. 20.1) indicate that a dangling bond is electronically active with energy levels in and near the gap. The formation of Si-H bonds saturates these bonds and moves the relevant states far from the gap. Only states associated with unsatisfied Si-H bonds and with traditional donors and acceptors remain in the gap, and the behaviour of the latter is similar to that in crystalline semiconductors. The nearest-neighbour distance between Si atoms is the same as in the crystal, and the density of amorphous Si is only a few per cent less than that of single-crystal Si. There is some evidence that the Si-H bonds are metastable, and that movement of hydrogen takes place between different bonds (Street 1991). The electronic structure of an amorphous semiconductor differs from its crystalline counterpart; despite the absence of long-range order, and a band structure in the conventional sense, there is still a principal bandgap. The band-edge densities of states do not have the sharp E energy dependence, but rather an exponential tail brought about by electron states localized in regions of lower potential energy within the amorphous network; these states are spread over a range with an energy scale E0 ∼ 0.1 eV associated with it (Fig. 20.l(b)).
The theory of light scattering from rod-like polyelectrolytes
Authors: Odijk Theo
Published: November 2023

A significant class of polyelectrolytes consists of slender, rod-like particles. Important examples include biopolymers such as short double-stranded DNA, helical xanthan, schizophyllan, F-actin, tobacco mosaic virus and fd virus. They may be semi-flexible but if the ratio of the persistence length to the contour length is smaller than unity, it becomes useful to model the polyions by charged rods. Inorganic colloids such as vanadium pentoxide and boehmite form another interesting subclass which may be considered completely rigid rods for most practical purposes. My objective here is to present a virial theory for the scattering by semi-dilute and concentrated isotropic solutions of rod-like polyelectrolytes, albeit under excess salt conditions.
Scattering fron1 concentrated polymer solutions
Authors: Nicolai Taco , Brown Wyn
Published: November 2023

Following the development of scaling theories by de Gennes and coworkers, a main focus of interest in polymer-solvent systems has been the so-called semi-dilute regime. Semi-dilute solutions are those having a very low polymer volume fraction and at the same time a strong overlap of the polymer coils.
Scattering properties of ternary polymer solutions
Authors: Borsali Redouane
Published: November 2023

To achieve a better understanding of polymer mixture properties, considerable effort has been made, over the past decade, on the static and the dynamic behaviours both in solution and in the bulk, from theoretical and experimental points of view. The aim of this chapter is to discuss the scattering properties of these systems on the basis of recent developments and to emphasize how one extracts important parameters such as the mobility of the chains (diffusion process) and the interaction parameter (compatibility) which control the dynamics and the thermodynamics. Using linear response theory and the random phase approximation (RPA), it has been shown that two relaxation modes describe the dynamic behaviour of incompressible polymer/polymer/ solvent systems. The first mode characterizes the total polymer concentration fluctuations and reflects the collective motion of all the polymer chains with respect to the solvent (excluded volume effect).
Light scattering in complex micellar systems
Authors: Schurtenberger Peter
Published: November 2023

Surfactants in solution exhibit a complex aggregation behaviour as a result of a delicate balance of opposing forces. Micellar solutions and microemulsions represent thermodynamically stable liquid dispersions containing surfactant aggregates, which can often be found in a large region of the phase diagram of two-or multi-component surfactant systemsP-In micellar dispersions, the aggregates are formed by self-assembly of surfactant monomers. While micelles are frequently spherical, they can also exhibit a sphere-to-rod transition and even grow to giant flexible and polymer-like aggregates. This micellar growth can be induced by a reduction in the so-called spontaneous curvature H0due to a change in a ‘control parameter’ such as temperature (in non-ionic surfactant systems), ionic strength (in ionic surfactant systems) or cosurfactant concentration, which subsequently results in a characteristic transition in the particle morphology from spheres to cylinders to lamellae.
Light scattering by block copolymer liquids in the disordered and ordered state
Authors: Štěpanek Petr , Lodge Timothy P
Published: November 2023

Block copolymers form a very important class of materials and are attracting increased attention because of their unique and widely variable properties. Block copolymers are macromolecules built of sequences of distinct repeat units. The number and chemical nature of the blocks can be varied but, most frequently, only two blocks, A and B, or three blocks A, B and C, are utilized. These can be used to generate a variety of chain architectures of which the most common types, both in laboratory experiments and in industrial applications, are AB diblock or ABA triblock copolymers. Less frequently, block copolymers of type ABC or (A–B)n are utilized.
Size distributions from static light scattering
Authors: Hallett F Ross
Published: November 2023

A knowledge of particle size distributions is central to innumerable scientific and applied problems in analytical chemistry, chemical physics and biophysics, atmospheric sciences and a host of other disciplines. A wide variety of techniques has been used to measure particle sizes These include dynamic light scattering (DLS), static light scattering (SLS), turbidimetry, small angle diffraction, optical particle counting, velocimetry, small angle X-ray and neutron scattering, size exclusion chromatography, electron microscopy, sedimentation and sieving/filtering. No one technique is suited for all particles and all conditions.
Quark Bilinear Operators
Authors: Ripka Georges
Published: November 2023

Meson fields couple directly to bilinear operators which carry the same quantum numbers. They can be introduced into quark actions so as to linearize products of quark bilinears (section 4.3). In some cases, it is useful to eliminate completely the quark field from the effective action, in favor of the meson fields. So-called bosonized forms of effective actions are obtained this way.
Static applications
Authors: Leupold H A
Published: November 2023

The advent of rare-earth permanent magnets (REPM) has brought about magnetic structures that were previously impracticable [Rot78, Tau85]. So different are these remakable materials from the earlier magnets that conventional design wisdom is inadequate to fully exploit their unique characteristics. Indeed, the conventional approach can lead to error or to the employment of quite inappropriate design procedures. The salutary characteristics stem from two basic attributes of the earth materials: (i) large intrinsic moments per unit volume; (ii) extraordinarily high resistance to demagnetization by external or internal demagnetizing fields.
Light energy
Authors: Akhmanov S A , Nikitin S YU
Published: November 2023

The energy flux carried by an optical wave. Optical beams and pulses: energy, power, and intensity. The spatial and temporal compression of light energy. Basic concepts of photometry. The capability to carry energy is one of the fundamental properties of light. The notion of electromagnetic energy is shown to emerge from Maxwell theory. The possibilities for spatial and temporal compression of optical energy are discussed and numerical estimates given.
Emission from an oscillator ensemble
Authors: Akhmanov S A , Nikitin S YU
Published: November 2023

From the dynamics of an oscillator to the statistics of an ensemble. Non-laser sources of light: intensity, polarization, and radiation directivity pattern. Radiation statistics of independent oscillators. The radiation spectrum. Mechanisms of spectral line broadening. Natural broadening. Doppler broadening. Collision-induced broadening and the shift of a spectral line. Dicke’s effect: collision-induced narrowing of a Doppler spectral line in a dense gas.
A linear oscillator in an optical field
Authors: Akhmanov S A , Nikitin S YU
Published: November 2023

Absorption of light by an oscillator and by an oscillator ensemble. The Bouguer law. Absorption spectroscopy. Decrease in the phase velocity of light propagating in a medium and the index of refraction. An inhomogeneous ensemble of oscillators. Homogeneous and inhomogeneous widths of spectra. Excitation by a short pulse-energy relaxation and dephasing. Principles of frequency- and time-domain spectroscopy.
Non-equilibrium Simulations of the Ising model
Authors: Newman M E J , Barkema G T
Published: November 2023

As our first example of the ideas introduced in Chapter 9 we now look at how the using model comes to equilibrium. As well as being a simple demonstration of most of the important ideas of out-of-equilibrium Monte Carlo simulation, our studies of the using model also tell us about real physics. As we explain in the next section, the equilibration of the using model below its equilibrium phase transition temperature sheds light on the physical phenomenon known as “spinodal decomposition”.
Monte Carlo Simulations in Surface Science
Authors: Newman M E J , Barkema G T
Published: November 2023

In the last chapter we used the results of simulations of the Ising model to study the growth of domains under spinodal decomposition. In this chapter we look at another use of the Ising model in quite a different field: surface science.
Random Numbers
Authors: Newman M E J , Barkema G T
Published: November 2023

The fundamental constant which links all Monte Carlo methods together, the common factor which makes them all Monte Carlo methods, is that they contain an element of randomness. Things happen in a probabilistic fashion in a Monte Carlo calculation, and it is only the average over many unpredictable events that gives us an (approximate) answer to the question we are interested in. To generate such unpredictable events, all Monte Carlo methods require a source of random numbers. There are many ways of generating random numbers. In this chapter we examine some of the most common of them.
Nonlinear Magneto-Optical Studies of Ultrathin Films and Multila Yers
Authors: Rasing Th.
Published: November 2023

The strong activity and success in magnetic thin-film research is based on the current developments in surface and material science, enabling the manipulation and control of thin-film structures on the atomic level and the parallel development of many spin-appended derivations of surface science tcchnigues.1 Some of the most exciting recent discoveries, like the giant magnetoresistance (GMR) and the oscillatory exchange coupling, are related to the properties of multilayers of alternating ferromagnetic and paramagnetic layers. As the inter face between these layers appear to play an essential role for these phenomena and consequently for the device properties based on them, a detailed study of the magnetic interface properties is needed.
Theory for Nonlinear Optics at Interfaces and in Thin Films of Metals: Selected Problems
Authors: Luce T A , Bcnnemann K H
Published: November 2023

We focus here on some important problems to supplement and extend the theory outlined by Hiihner, to demonstrate the potential of nonlinear optics regarding the analysis of the electronic and magnetic structure of interfaces and thin films, and to sketch some interesting problems to be solved. First, we summarize the most important general properties of second harmonic generation (SHG) from metals. Then, we discuss some problems reflecting the inter play of effects due to the optical transition matrix elements and the electronic energy spectrum availahlc for these transitions.
Introduction
Authors: Ejiri H , Toki H
Published: November 2023

The nuclear physics of nucleon-hadron many-body systems is concerned with fundamental structures of interacting nuclear particle systems. Here, nuclear particles are particles involved in nucleon/hadron systems and interactions therein. The particles to be considered are primarily quarks in the case of hadrons, and are mostly hadrons in the case of nuclei. Nuclear interactions associated with them are strong, weak, and electromagnetic ones. They are given by gauge fields with relevant gauge bosons. Then the gauge bosons to be considered in quark-lepton systems are gluons, weak bosons, and photons. Leptons are necessarily involved in nuclear weak processes. Gravitational interactions are significant only in special cases in astrophysics, such as neutron stars and supernovae. In the case of nucleon-hadron systems, meson exchange interactions and effective nucleon interactions are used in place of the QCD gluon field due to confinement of quarks and spontaneous chiral symmetry breaking.
Spin—isospin giant resonances by charge-exchange reactions
Authors: Fujiwara Mamoru
Published: November 2023

A nucleus primarily consists of protons and neutrons. This microscopic world is governed by a strong force, i.e. the nuclear interaction mediated by the exchange of pions and other heavy mesons between the nucleons. If the interactions between the constituents in a nucleus are known, the behaviour of this microscopic world can, in principle, be described. But, the actual situation is not so simple since the many-body problem can be solved exactly only for two- and three-body systems with some basic physical assumptions. Thus, all theoretical analyses of nuclei need a model, the validity of which should be checked by experimental tests in order to confirm the underlying approximations or to improve them.
Breakup processes and cluster structures of light composite projectiles
Authors: Sakuragi Y
Published: November 2023

In nuclear reactions induced by light composite projectiles, many of which are loosely bound systems, projectile breakup takes place strongly as a real or a virtual process and is known to play an important role in various nuclear reactions. In this chapter, we review the present status of our understanding of reaction mechanisms relevant to the nuclear breakup processes and their role in nuclear reactions induced by light composite projectiles.
Physics of snowballs—impurity ions in superfluid helium
Authors: Takahashi N , Shimoda T
Published: November 2023

The strange behaviour of liquid helium has been attracting the attention of quite a number of physicists ever since helium was liquified and is still doing so after almost a century. It may well not be an exaggeration to say that new precise measurements of physical quantities concerning liquid helium succeed in reviving discussions about our physical insights into the problems of liquid helium.
Atomic physics with cyclotron beams
Authors: Katayama lchiro
Published: November 2023

Why atomic physics at a cyclotron laboratory? ‘The interaction is very clear, so what is left for study?’ —this is often what I was asked when we started atomic collision studies at RCNP. I hope this report provides some answers to the question. Firstly, I would like to remark on the so-called ‘Massey criterion’, which states that between a projectile and an electron, in a certain orbit in a target atom, the strongest interaction is expected when the velocities match each other. As the velocity of a K-shell electron in Pb atom equals that of a 160 MeV proton, this implies that, in order to study the excitation of inner-shell electrons in heavy atoms, one needs very high energy ion beams. Secondly, there is one other aspect, viz. the potential usage of a foil target. All the atomic physics experiments which were done at RCNP utilized thin foils, even though some of them aimed to study a single collision process, e.g. electron capture and loss process. Others were designed to study solid state effects such as channelling, convoy electrons, stopping-power experiments, and so on. (Although they are not topics from pure atomic physics in a strict sense, we include them in this review.) Even for these solid state effect experiments, the use of high energy beams from cyclotron is more effective, since it relaxes us from ultra-high vacuum condition. There is another advantage in studying atomic collisions at RCNP: one can use the high-resolution magnetic spectrograph RAIDEN, which is quite unique if one compares it with facilities available at other institutes.
Nuclear physics with strange flavour
Authors: Kishimoto Tadafumi , Motoba Toshio
Published: November 2023

It is well known that quarks are real constituents of hadrons. The interactions among quarks are described by Quantum ChromoDynamics (QCD), where the interaction between three colour charges is mediated by gluons. Nuclei are made up of nucleons held by the strong interaction, though it has been quite rare to require explicit quark degrees of freedom to understand many aspects of their low-energy phenomena. Since hadrons are colour singlets, the interactions among nucleons are the residual interactions of quarks, which is responsible for the success of the meson theory.
Quark nuclear physics
Authors: Toki Hiroshi , Suganuma Hideo
Published: November 2023

In traditional nuclear physics, protons and neutrons, the constituents of a nucleus, are assumed to be point particles and are described by a Hamiltonian with a kinetic term and an interaction term, possibly obtained from the Nucleon—Nucleon (NN) scattering data. The purpose is then to describe the binding energies of nuclei, their structures, decay properties, reaction rates, etc. The fundamental model used is the shell model [1].

About 20 years ago, other degrees of freedom were introduced to nuclear physics. The sensational one is pion condensation, in which the energy of pion becomes zero in nuclear matter, due to the interaction of pions with the nuclear medium, which includes also the delta isobar [2,3]. More recently, deep inelastic scattering has been used to probe the nucleons in nuclear medium and to study differences from their counterparts in free space, which is called the EMC effect [4]. A more drastic process is the production of high-density and high-temperature nuclear matter by relativistic heavy-ion collisions [5]. Such processes could even reduce nuclear matter from hadronic to a quark—gluon plasma phase.
The production of neutrons
Authors: Willis B T M , Carlile C J
Published: November 2023

Much of the matter in the world around us consist of bound neutrons. The free neutron is an unstable particle, undergoing a three-body decay to a proton, an electron and an anti-neutrino, with a half-life of about 10 minutes. Neutrons are produced in a variety of nuclear reactions which includes fission, photofission, spallation and fusion. For scattering experiments the most significant of these are fission and spallation.
Liquids, glasses and amorphous materials
Authors: Willis B T M , Carlile C J
Published: November 2023

In this chapter, we shall discuss the application of neutron scattering to the study of liquids, glasses and amorphous materials. Our principal concern will be the understanding of the ‘structure’, or the spatial distribution, of the atoms in these disordered systems. The dynamics of the systems can be investigated by inelastic neutron scattering, but we shall only discuss inelastic scattering processes in so far as they affected the interpretation of data relating to structure.
Coherent inelastic scattering from single crystals: study of phonons and magnons
Authors: Willis B T M , Carlile C J
Published: November 2023

Experiments in inelastic scattering require the measurement of the energy transferred from (or to) the scattered neutron to (or from) the scattering system. In this chapter, we shall be concerned with the use of coherent inelastic scattering in the study of the lattice and magnetic excitations in single crystals.
Quasi-elastic scattering and high-resolution spectroscopy
Authors: Willis B T M , Carlile C J
Published: November 2023

Quasi-elastic neutron scattering (QENS) refers to those inelastic processes that are almost elastic. The term is usually considered to mean a broadening of the elastic line in the energy spectrum rather than the appearance of discrete peaks representing inelastic events. In the context of this chapter, it is also appropriate to include low-energy inelastic processes of energies up to 1 meV: this is because the energy and momentum transfers in both cases are similar and, therefore, the two kinds of measurement are usually carried out with the same type of spectrometer.
Basic plasma characteristics
Authors: Dendy R O
Published: November 2023

We start by considering an assembly that consists of an equal number of electrons with charge -e and ions (atomic nuclei) with charge +e. Suppose that these particles are initially uniformly distributed, so that the plasma is initially electrically neutral everywhere. Furthermore, let us assume that there is no random thermal motion, so that the electrons and ions are initially motionless. This idealized assembly is referred to as a cold plasma. We now perturb this system by transferring a group of electrons from a given region of space, leaving a net positive charge behind, to a neighbouring region which acquires net negative charge; see Fig. 1.1.
Motion of An Electron in An Undulating Magnetic Field
Authors: Luchini P , Motz H
Published: November 2023

The first step in studying the interaction of an electron beam with an undulator is, of course, the calculation of the electron trajectories in its field. In this chapter we apply to the undulator problem a Hamiltonian formulation which will allow us to gain an advantage from the ultrarelativistic character of the electron motion we are interested in. The required basic elements of Hamiltonian mechanics are summarized, for the reader's ease of reference, in Appendix A.
Magnet Design
Authors: Luchini P , Motz H
Published: November 2023

In this chapter consideration will be given to magnet design. The principle has already been described in Chapter 1 in connection with the original undulator, which had intertwined soft-iron pole pieces of north and south polarity attached to soft-iron bars of the respective polarity, and kept at constant magnetic potential by permanent magnets (magnetron magnets). In recent designs both linear and helical undulators (twisters) have been realized, using either permanent magnets or electromagnets, with or without iron, or a combination of both. We shall examine the various options in turn
Experiments and Applications
Authors: Luchini P , Motz H
Published: November 2023

While the undulator used for its spontaneous emission is a mature device, the undulator used as a free-electron laser is, today, still at an experimental (although advanced) stage. We conclude with a survey of some of the first free-electron laser experiments performed, selected for the purpose of exemplification amongst the many which we do not have enough space to describe, and of their proposed applications.
Schrödinger And Dirac Hamiltonians For A Central Field
Authors: Weinberger P
Published: November 2023

where t  s is the kinetic energy operator. Since central field solutions are very important for the calculation of the electronic structure of solid matter, it seems quite appropriate to discuss some of the symmetry properties of eqn (3.2) and the consequences thereof. This seems also to be necessary in order to mark the inherent differences between these two cases, namely the Schrödinger-type and the Dirac-type Kohn-Sham equations.
Single-Site Scattering
Authors: Weinberger P
Published: November 2023

So far it might seem that three different subjects have been dealt with in three different chapters, but this chapter and the following one will help to draw these previous chapters together. In a way, all that has been discussed so far is essentially preliminary material.
Multiple Scattering
Authors: Weinberger P
Published: November 2023

In terms of the T operator. Indeed both ways are used in the literature to describe the concept of multiple scattering. Here only the Lippmann-Schwinger equation for the T operator will be considered.
Charge Self-Consistency And Total Energies
Authors: Weinberger P
Published: November 2023

Within the 'constant k mode' the energy parameter E varies continously, implying that for a given order of the 'substitutional translational group', for example, the eigenvalues of an ordered system can in principle be determined exactly. This is important, because within this mode all van Hoove singularities caused by topological k points are properly described.
Applications Of Multiple Scattering II: Physical And Transport Properties Related To The Fermi Energy
Authors: Weinberger P
Published: November 2023

In this chapter a selection of physical properties will be discussed, all of which are related to the one-particle Green function at the Fermi energy. Also included is a short discussion of electrical conductivity, because quite frequently this quantity is described in terms of an integral over the Fermi surface. It should be noted that whenever other types of particles (phonons, etc.) are also involved in this chapter, the theoretical description will be restricted to the electronic part only.
Crystal-Field Excitations In The Light Rare Earths
Authors: Jensen Jens , Mackintosh Allan R
Published: November 2023

A magnetic ion in a rare earth metal experiences a crystalline electric field from the surroundings, which gives rise to an overall splitting of the order 10-20 meV of the ionic ground-state J-multiplets. Crystal-field excitations are collective normal modes of the system, associated with transitions between the different levels of the ground-state multiplets. Even though there is an obvious qualitative difference between the crystal-field excitations in paramagnetic Pr and the spin waves in the isotropic ferromagnet Gd, it is not in general easy to give a precise prescription for differentiating between the two types of excitation.