Chapter 15 is devoted to systems of identical particles and the associated quantum statistics. It is shown how the spin (whether integer or half-integer) determines fundamental features of the system’s behavior that cannot be obtained by approximate methods, in particular the exchange effects characteristic of states of two or more identical particles. The spin-symmetry relation is discussed in detail for both the Bose–Einstein and the Fermi–Dirac statistics. Quantum collective phenomena that are a defining feature of condensed matter, including phonons, superconductivity, Bose–Einstein condensates and the quantum Hall effect, are briefly introduced. Since most real quantum systems consist of subsystems in different quantum states that are mixtures of pure states, the chapter includes an introduction to the density matrix, its basic properties and its application to quantum statistics. It concludes with a critical discussion of decoherence and the significance of the collapse of the wave function.

Chapter 14 is entirely devoted to the electron spin and an introduction to quantum entanglement. The first part deals with the groundbreaking discovery of spin, its introduction into quantum formalism, and some of its most important effects on atomic spectra, notably the anomalous Zeeman effect. Historically, spin has been considered as an angular momentum that particles can have by the mere fact of their existence, which is called "intrinsic" and does not require any explanation. To address this shortcoming, Section 4 presents a possible explanation for the origin of electron spin as a result of its interaction with the vacuum field. Section 5 introduces the entangled system of two particles with spin, which provides an opportunity to discuss, necessarily schematically, the Schrödinger cat and the Einstein-Podolsky-Rosen thought experiment, as well as the Bell inequalities.

Chapter 3 discusses the verse and criticism of Ford Madox Ford and the poets later styled as ‘the forgotten school of 1909’. It explores how Ford, along with other Edwardian writers like Edward Storer, T. E. Hulme and F. S. Flint, began to use ideas about impressionism to conceive of what ‘Modern Poetry’ (to use the title of Ford’s important essay of 1909) might look like. Specifically, it examines the forgotten school’s shared use of the language of impressionism as a vehicle for accommodating new subjects and metrics within English poetry, with a particular focus on how this language shaped their arguments about vers libre. The chapter ties the metrical experimentation of the pre-imagist avant-garde to their broader conceptions of modernity and selfhood. It suggests that, if impressionism was the gravitational term which attracted several quite different poets, it also enabled them to pull together an interest in modern urban subject matter, a metaphysics associated with Pater and Bergson, and a range of ‘free’ poetic forms which anticipate some of the major achievements of modernist verse.

Africa is disproportionately affected by economic sanctions imposed by countries in the Global North, particularly by the US. A little-studied dimension of these sanctions programs is their humanitarian impact, particularly given that these programs are often justified as being “smart” or “targeted” and thus negating such collateral effects. This chapter argues that the opposite is true in the area of financial inclusion. It is due to the difficulty of complying with US banking regulations, which is exacerbated by these sanctions programs, resulting in a “chilling effect” whereby retail banks choose to withdraw from the African market rather than risk violating US law and incurring the crushing penalties that follow from that, including the possible debarment from the Federal Reserve System and the inability to access the US financial system. The dollar’s unrivaled status as the global reserve currency makes the risk of incurring this financial “death penalty,” as it is sometimes termed, too great to bear. This withdrawal of retail banking services severely hampers financial inclusion in Africa and has a direct, negative effect on efforts at poverty reduction and sustainable development, one which is rarely a part of policy discussions about sanctions, yet raises significant social justice issues.

Starting from the observation that impressionism is one of the forms to which Ezra Pound responds most frequently in his early writings about art and poetry, Chapter 4 examines the vacillation between admiration and disinheritance which characterises Pound’s remarks about impressionist aesthetics, with a particular focus on how this ambivalence shaped his prescriptions for imagist poetry. Reading Pound’s early verse alongside his essays on visual art and his critical dialogues with Ford, Flint and others, the chapter suggests that his efforts to segregate imagism from certain forms of impressionism camouflage a considerable debt. Indeed, it argues that Pound’s responses to impressionism become inseparable from his theory of the Image, even (or perhaps especially) when he attempts to dissociate the two ideas. The emphases of these responses frequently change, but they are always drawn towards a central term, with which they are in productive, if divided, tension. The chapter suggests that it is partly out of this tension that Pound’s concept of the Image begins to emerge, acquiring its own mirrored ambiguities in the process.

Chapter 5 familiarizes the student with some of the most basic features of quantum systems, by applying the Schrödinger equation to simple, one-dimensional problems. It shows that it is possible to obtain qualitatively correct conclusions about the behavior of quantum particles in the presence of more or less arbitrary potentials by replacing them with piecewise-constant potentials, which greatly simplifies the mathematics. Replacing the real potential with a simpler one that retains its basic characteristics has the great advantage of allowing us to study the essence of the physical situation, as illustrated by the examples of the one-dimensional potential step, the square well, the square potential barrier and the symmetric double well. These examples are used to discuss specific features such as quantum tunneling, and applications such as masers and molecular clocks.

This Preface begins with a passage from Pierre Auguste-Renoir’s diary, in which he records the following aphorism: ‘Everything that I call grammar on primary notions of Art can be summed up in one word: Irregularity.’ Taking Renoir’s idea of irregularity as a starting-point, this chapter sketches out the historical origins of impressionism and gives a brief outline of its formal and thematic variety, before gesturing to its significance as a cultural and stylistic reference point for writers at the turn of the century, including the group of British, Irish and American poets at the heart of the present study.