bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrons in a Crystal Get Their Bands, Gaps, and Masses
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • How are the free electron eigenfunctions and energy eigenvalues modified in a periodic potential of a crystal? • Which free electron states are most violently modified, and which states are left almost unaltered by the periodic potential? • How does the periodic potential change the continuum of allowed energies by introducing bands of allowed energies separated by energy gaps? • How do the electron energy states near the edges of allowed bands acquire an effective mass, and what are the concepts of electrons and holes?
k · p Bandstructure
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • How to view the electron momentum as a perturbation and map the bandstructure problem to the perturbation theory result of quantum mechanics, • Directly apply the results of perturbation theory to obtain the k · p bandstructure E(k) for semiconductors, • How symmetry of states and momentum matrix elements between the valence and conduction bands determine the curvature and effective mass of the bands, and reveal important relations between bandgaps and effective masses, and • How spin-orbit interaction is included in the semiconductor bandstructure.
1, 2, 3 …∞: Pseudopotentials and Exact Bandstructure
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • The exact solutions of the bandstructure of crystalline solids. • Pseudopotentials: what they are, why they work, and why they are so powerful. • Example calculations of full bandstructures of a few semiconductors (e.g. Silicon, GaAs, GaN) on a laptop. • Pseudopotentials as the precursor to density functional theory techniques for electronic bandstructure and beyond.
Carrier Statistics and Energy Band Diagrams
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • What are the mobile carrier concentrations in an intrinsic, pure semiconductor? • How can we vary the mobile carrier concentrations in semiconductors by factors of ∼ 1010 by doping? • What is the carrier statistics and energy band diagrams in homojunctions: when the semiconductor is the same, but the doping varies in space? • What is the carrier statistics and energy band diagrams in heterojunctions: when both the semiconductors and the doping variy in space?
Controlling Electron Traffic in the k-Space
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • The first part of this chapter succinctly discusses the quantum physics of electron and hole statistics in the bands of semiconductors, the quantum mechanical transport of the electron and hole states in the bands, and optical transitions between bands. • The second part of the chapter summarizes the core concepts of the physics, and electronic and photonic applications of semiconductors and nanostructure based devices such as diodes, transistors, solar cells, light emitting diodes, and lasers.
Taking the Heat: Phonons and Electron-Phonon Interactions
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • What are the effects of phonons on the properties of solids in general, and semiconductors in particular? • What are the allowed modes, energy dispersions, density of states, and quantum statistics of phonons in semiconductors? • How do phonons influence the optical, electronic and thermal conductivity of semiconductors? • Which device applications of semiconductors are rooted in the properties of phonons?
Running Circles: Quantum Magnetotransport
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • What are the semi-classical effects of magnetic field on the properties of semiconductors? • What are the quantum effects of magnetic fields on the properties of semiconductors? • How can Shubnikov de Haas oscillations and the Quantum Hall effect be explained from quantum transport in semiconductors? • How can magnetic fields be mimicked in semiconductors through topological aspects in bandstructure?
Light–Matter Interaction
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • How can we capture the interaction of semiconductors with photons quantum mechanically? • How can we explain the optical absorption spectrum of bulk semiconductors in equilibrium? • How are these properties modified in low-dimensional semiconductor structures such as quantum wells and quantum dots? • What are the characteristics of optical processes other than interband transitions such as absorption by free-carriers, excitons, impurities and intersubband transitions, and how do they differ from interband transitions?
Heavenly Light: Solar Cells and Photodetectors
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • How is light energy converted to electrical energy by semiconductor solar cells, and what are the fundamental limits of their efficiencies? • How are optical absorption processes in semiconductors used to make efficient photodetectors, and over what ranges of wavelengths, timescales, and efficiencies can they operate? • What is the operating principle of semiconductor based optical modulators, and what are their limitations?
Reach for the Stars: Lasers and LEDs
Authors: Jena Debdeep 
Published: August 2022

Abstract
This chapter discusses the following questions: • How does the absorption coefficient of semiconductors change under nonequilibrium conditions? • What are the requirements for spontaneous and stimulated emission of light from semiconductors? • How do LEDs operate based on spontaneous emission? What are their quantum efficiency limits? • What are the principles of operation of semiconductor lasers, and how is stimulated emission sustained? • How can we reconcile the quantum nature of light by quantizing the electromagnetic field?
Women Saving the World
Authors: Le Roux-Rutledge Emily 
Published: August 2022

Abstract
Radio has long been used as a tool for development—particularly when promoting gender equality and women’s empowerment—but far more attention has been paid to local community radio than to radio with a global reach. This chapter seeks to understand how a far-reaching global radio programme, the BBC’s 100 Women series, represents women from low and lower middle-income countries, and portrays their role in development. Narrative analysis reveals two prominent meta-narratives, or frames, in the series: one in which a woman is portrayed as a local phenomenon, and the other in which she is portrayed as a global success. Both frames reproduce a standard development trope, in which women are presented as ‘saviours’ driving development through their community mindedness and altruism, rather than as multifaceted human beings intrinsically entitled to equality.
Contemporary Arts Festivals in Nigeria and Nepal
Authors: Sage Caroline 
Published: August 2022

Abstract
A growing number of contemporary arts festivals in the Global South are increasingly engaged in topics and discussions that are important for development practice and discourse. Drawing on Contemporary arts festivals in Nigeria and Nepal as case studies, the chapter examines various ways the ‘cultural hybridity’ inherent in such festivals intersects with more linear development narratives and practice, providing spaces for the global and local voices and relationships to be contested, debated and redefined. The chapter explores four different elements at play in each of the festivals: Representation and the reclaiming of ‘Third World’ narratives; Deliberation and contestation on value, politics and identity; Market relations, livelihood strategies and promotion; and Reimagining Development. Ultimately the chapter argues that the development industry should pay more attention to the opportunities provided by such events for conversations and engagements which could drive genuine co-creation of development narratives and practice.
Reforming Age Discrimination Law
Authors: Blackham Alysia 
Published: August 2022

Abstract
Age is a critical issue for labour market policy. Both younger and older workers experience significant challenges at work. Despite the introduction of age discrimination laws, ageism remains prevalent. This book offers a roadmap for the future development of age discrimination law in common law countries, to better address workplace ageism. Drawing on theoretical, doctrinal, and empirical legal scholarship, and comparative perspectives from the United Kingdom, Australia, and Canada, the book provides a grounded critique of existing age discrimination laws and their enforcement, and puts forward concrete suggestions for legal reform and change. It examines the challenges and limitations of existing legal frameworks and the individual enforcement model for addressing age discrimination in employment, mapping the stages of claiming, negotiation, or alternative dispute resolution, and hearing and judgment, using mixed method case studies of the enforcement of age discrimination law in the United Kingdom and Australia. The book puts forward a fourfold model of reform to strengthen age discrimination law, to improve the individual enforcement model, strengthen positive equality duties, bolster the roles of statutory equality agencies, and enhance collective enforcement. The book critically considers how these options might address the limits of existing laws, and the practical measures necessary to ensure their success.
The Enduring Challenge of Age Discrimination
Authors: Blackham Alysia 
Published: August 2022

Abstract
This chapter provides an overview and justification of the book’s scope, theoretical framework, and method. Drawing on data from the United Kingdom, Canada, and Australia, it considers the challenges and opportunities of demographic ageing, and the workplace experiences of older and younger workers. It critically considers the nature and prevalence of age discrimination in employment, arguing that age discrimination is pervasive, subtle, and socially accepted, occurring across the life-cycle of employment from recruitment to termination. The chapter argues that the enduring prevalence of age discrimination at work presents a strong case for critique and reform of the legal framework; and posits that the very nature of age discrimination may make existing models of enforcement problematic. The chapter presents reflexive law and regulatory theory as useful theoretical frameworks for critiquing the enforcement and legal efficacy of age discrimination laws. It provides an overview of the book’s empirical mixed methods research design, which synthesizes qualitative, quantitative, doctrinal, and comparative research methods.
Positive Duties
Authors: Blackham Alysia 
Published: August 2022

Abstract
This chapter critically analyses the extent to which positive duties offer a viable alternative or addition to the individual enforcement of age discrimination law. Drawing on a theoretical model grounded in reflexive law and regulatory theory, the chapter evaluates the theoretical potential of positive duties to enhance discrimination law, and identifies key criteria for making positive duties effective in practice. It maps existing positive duties in the United Kingdom and Australia, and critiques their operation using this model. The chapter argues that positive duties have radical potential to effect organizational change, but do not yet meet the requirements for effective second-generation regulation. Focusing on four interlocking limitations of existing positive duties—self-regulation by organizations, consultation and engagement, central scrutiny, and individual enforcement—it proposes reforms to strengthen existing provisions.
When Things Grow Many
Authors: Schulman Lawrence 
Published: August 2022

Abstract
Methods of statistical mechanics are applied to many natural phenomena in the limit of large numbers of constituents. Applications include linguistics, finance, urban segregation, firefly and cardiac synchrony, Supreme Court voting, ecology, flocking, epidemics, crowd control, genetics, neurology, and so on. There is even a bit of physics (luminescence, large-scale structure, morphology). Suitable for use by advanced undergraduates (in any field) and graduate students. Some mathematical background is required although there are explanations of more advanced topics (e.g. fractals).
Ferromagnetism
Authors: Schulman L. S. 
Published: August 2022

Abstract
Magnetism and order parameters are discussed in both mean field theory and exact treatments. An example of stochastic dynamics for the Ising model is given. The Curie–Weiss model is defined as a system in which mean field theory is exact. For this system (consisting of N spins) the fluctuations at the critical point are the fourth root of N, rather than the square root as is the case when the variables are independent.
Social sciences
Authors: Schulman L. S. 
Published: August 2022

Abstract
Applications abound in the social sciences. Economics and finance involve both power laws and herd phenomena. Linguistics is another place where (maybe) power laws have been found. City populations seem to follow a power law, with power near the value 1, a value that occurs in many other applications. There are other issues connected to cites, for example discrimination in housing. This too can be modeled and analyzed. Another problem that is dealt with from the standpoint of “many” is elections and voter models (the same formulas also turn up on finance). There are also applications to crowd control and traffic.
Physical sciences
Authors: Schulman L. S. 
Published: August 2022

Abstract
This chapter deals with traditional physics so as to cast light on the main themes of the book. A particular problem of luminescence is discussed to show how power laws can be faked. There is also discussion of a fractal universe. That is, it may be that galaxies are arranged hierarchically as far as the eye (with aids) can see. This is not accepted by most cosmologists, but is an interesting study. Finally, the chapter deals with the morphology of galaxies.
Tensor algebra
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 5 introduces the mathematical tools needed for the study of relativity, namely, tensor analysis. To work effectively in Newtonian theory, one really needs the language of vectors, whereas, in relativity, one needs the language of tensor analysis. This part of the book is devoted to learning this formalism, which is a precondition for the rest of the book. The notion of a differentiable manifold is first introduced. The chapter then introduces tangents to curves and normals to surfaces as prototypes for vectors and co-vectors, respectively. It then goes on to introduce the elements of tensor algebra, including the tensor product and the notion of contraction. It ends by giving a coordinate-free interpretation of vector fields in terms of derivative operators.
Tensor calculus
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 6 introduces tensor calculus and deals with two important generalizations of partial derivatives, namely the Lie derivative and the covariant derivative. The metric tensor, which is used to measure distance on a manifold, is introduced and it is shown how this defines the metric connection which is used to define the covariant derivative. The very important notion of Riemann curvature is introduced using covariant derivatives and an explicit expression is derived for the Riemannian tensor. It is also shown how to decompose the curvature into a Ricci tensor part and a Weyl part
General relativity from a variational principle
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 11 provides a more mathematical derivation of the field equations from a variational principle as was first suggested by Hilbert. Many tensor identities are best derived using the technique of geodesic coordinates. As well as considering the action to be dependent on the metric, this chapter introduces the Palatini approach which depends separately on a connection and a metric. The chapter ends by briefly introducing a matter term into the Lagrangian in order to obtain the Einstein Lagrangian and then the full Einstein field equations. This sets the scene for the next chapter, which considers the energy–momentum tensor.
The energy-momentum tensor
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 12 looks at the three most important energy–momentum tensors in general relativity, namely the energy–momentum tensors for incoherent matter or dust, a perfect fluid, and the electromagnetic field. The treatment is neither exhaustive nor complete, but is sufficient for generating the explicit expressions needed in future chapters. In passing, we look at a tensor formulation of Maxwell’s equations governing the electromagnetic field. It is shown how the electromagnetic energy–momentum tensor can be obtained from a Lagrangian description of the electromagnetic field, which in turn leads to the Einstein–Maxwell equations. This is extended to the case of a general-matter Lagrangian, and various examples are considered. Finally, a physically realistic condition for a matter field called the dominant energy condition is introduced.
Classical experimental tests of general relativity
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 16, the final one in Part C, focuses on the tests of general relativity that can be carried out in the solar system. However, these tests are really tests of general relativity in the weak field regime, in which the gravitational effects are not significantly different from the corresponding Newtonian ones. The chapter uses the Schwarzschild solution to derive the three classical experimental tests of general relativity, namely the test of the equivalence principle, the advance of the perihelion of Mercury, and the bending of light. A fourth test, the so-called Shapiro time delay, is also considered. In the final section, the parameterized post-Newtonian formalism (PPN parameters, for short) is introduced. This is used to quantify the outcome of the experimental tests and show how the current experimental evidence is strongly in support of Einstein’s theory.
Non-rotating black holes
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 17 looks at non-rotating black holes. The exterior solution is the Schwarzschild metric. However, in the original Schwarzschild coordinates, it appears to have a singularity at the surface. It turns out that this is not a physical singularity but only a coordinate singularity and it is possible to introduce new coordinates, the so-called Eddington–Finkelstein coordinates, in which the metric is regular at this surface and which allow one to extend the metric for all positive values of the radial parameter r. However, a scalar invariant constructed from contracting the curvature with itself diverges as r tends to 0, which shows that there is a genuine curvature singularity there. Space-time diagrams and spatial diagrams are used to discuss the singularity structure and lead to the location of the ‘event horizon’, which has the property that any signal emitted inside this radius cannot escape to the exterior region.
Charged black holes
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 19 deals with the description of a charged black hole. Such a solution has many of the features of a rotating black hole but is mathematically much more tractable. The chapter begins by looking at the electromagnetic field of a charged point particle and calculates the associated energy–momentum tensor. This is used to derive the Riessner–Nordström solution, which describes the gravitational and electromagnetic fields outside a charged spherical body. The importance of this solution is that its structure is in many ways similar to that of the more complicated Kerr solution describing rotating black holes but is mathematically simpler to deal with. The Penrose diagram of the maximum analytic extension is then obtained and the structure of the singularities and event horizons investigated.
Exact gravitational waves
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Rather than looking at solutions of the linearized Einstein equations, Chapter 22 looks at exact solutions of gravitational waves. In looking for exact solutions, it is useful to assume that the metric has a high degree of symmetry. However, it is only possible to do this in special situations such as in the case of cylindrical gravitational waves and plane gravitational waves. Nevertheless, such solutions are of great interest from the theoretical point of view as they show that generically gravitational waves appear to focus as they pass through each other. This leads to the prospect of gravitational singularities at some distant time in the future. The chapter also investigates Einstein–Rosen waves, impulsive plane gravitational wave, colliding impulsive gravitational waves, and colliding gravitational waves.
The classical cosmological models
Authors: d’Inverno Ray , Vickers James 
Published: August 2022

Abstract
Chapter 25 mostly discusses the mathematical features of the classical FRW cosmological models (where FRW stands for Friedmann–Robertson–Walker) that one obtains by solving the Friedmann equation. It looks at how these relate to the observational evidence as well as considering some more sophisticated models in the next chapter. It also provides a more complete analysis of the various Friedmann models. These include Einstein static space, de Sitter space, and anti-de Sitter space. The early epochs of the universe and the historically significant steady-state theory are next discussed. The conformal structure of these solutions is examined and the Penrose diagrams constructed. This shows that a number of solutions have particle horizons and/or event horizons, which means that only a portion of the space-time can be seen by any observer.
Über Sinn und Bedeutung
Authors: Picardi Eva 
Published: August 2022

Abstract
This chapter constitutes a thorough examination of Über Sinn und Bedeutung with illuminating forays into how the issues at play in this text became the object of heated debates in subsequent philosophy of language. Chief issues are Frege’s treatment of identity and identity criteria, the objectivity of sense, his views about oratio obliqua and the doctrine of indirect senses, synonymity and its relationship with Benson Mates’s paradox and Alonzo Church’s synonymous isomorphism, as well as the recognition of the role that context may play in the determination of the thought expressed by a sentence in which indexicals and demonstratives occur.
The Chemistry of Concepts
Authors: Picardi Eva 
Published: August 2022

Abstract
The chapter examines the origins and value of the comparison, drawn by Frege, between chemical molecules and the composition of concepts within a proposition. While the use of chemical metaphors in logic is not new—as testified in the work of Schopenhauer, Mill and Peirce—Frege’s use is crucial to the development of his objective and anti-psychologistic account of concepts. Furthermore, it testifies to the priority of sentences expressing a judgement over their component parts. Special attention is given to Frege’s notion of ‘unsaturatedness’ and to his way of connecting this theme with the possibility of deriving quantified sentences from their atomic instantiations and vice versa.