Economic sanctions are often deployed as political tools, but their impact extends far beyond their intended political targets. This study examines how intensified sanctions on Iran have affected the human security of Afghan migrants, a population already facing structural vulnerabilities. Drawing on fifty-three semi-structured interviews conducted between 2015 and 2018 with Afghan migrants and experts, the research explores two critical dimensions of human security: economic stability and access to healthcare. The findings reveal that while lower- income Afghan workers in unskilled sectors managed to retain employment due to demand for cheap labor, skilled workers and business owners faced significant economic hardship. At the same time, healthcare access deteriorated as financial constraints reduced government support and international assistance failed to meet growing needs. As the Iranian government adjusted its policies to prioritize its own citizens, Afghan migrants were further marginalized. This study underscores the unintended humanitarian consequences of economic sanctions. It highlights the need for a more nuanced approach to policy design. This applies both in the implementation of sanctions and in the response of host governments. A careful approach is necessary to ensure that vulnerable migrants are not disproportionately affected.

This chapter explores how US allies participate in US-led sanctions, focusing on South Korea’s response to Iranian sanctions following the Comprehensive Iran Sanctions, Accountability, and Divestment Act of 2010 (CISADA). South Korea faced an acute dilemma between supporting the US, its strongest ally, and maintaining its valuable economic and diplomatic ties with Iran. While other US allies swiftly implemented their own independent sanctions following the US lead, South Korea ultimately developed a distinctive approach, creating a complex sanctions regime across finance, trade, transportation, and energy sectors, while simultaneously establishing a Korean won-based settlement system for commercial transactions with Iranian parties. This strategy proved highly successful, allowing South Korea to balance competing international pressures without jeopardizing its relationships with either the US or Iran. South Korea’s case highlights an underexplored dimension of sanctions alliances: how countries may reluctantly join sanctions alliances, driven more by the need to avoid alienating a powerful ally than by a genuine commitment to the sanctioning campaign. This chapter provides new insights into the hidden dynamics of sanctions alliances and the sophisticated diplomatic strategies employed by nations navigating complex international obligations.

Chapter 9 is devoted to a detailed study of the harmonic oscillator in one dimension. The time-dependent Schrödinger equation is used to construct the coherent oscillator packet with minimal dispersion, which provides an opportunity to appreciate the similarities and differences between the dynamics of the classical and quantum oscillators. In a second step, we study the stationary solutions of the oscillator, which represent one of the most important orthogonal sets of quantum eigenfunctions because of its many applications, properties, and relative simplicity. Further, the use of raising and lowering (or creation and annihilation) operators is shown to be a powerful way of dealing with both material and field oscillators in general. Finally, the problem of two coupled oscillators is used to generalize the Schrödinger equation to the case of more than one particle.

Chapter 19 introduces relativistic quantum mechanics, with the aim of providing the student with a basic knowledge of the subject and a link to more advanced courses in relativistic quantum theory. It begins by showing that when the Schrödinger equation is modified to make it consistent with special relativity, the result is the Klein–Gordon equation, which gives better qualitative agreement with experiment. Introducing the electron spin into the Schrödinger equation leads to the Pauli equation, which gives rise to important spin effects. By considering both special relativity and spin, one obtains the Dirac and the van der Waerden equations. The main properties and implications of Dirac’s equation are discussed, including the electron’s zitterbewegung. The solution of Dirac’s equation for the free particle is presented in detail, the hydrogen-like atom is shown to be exactly solvable, and the particle in an external electromagnetic field is included as a complementary material.

This chapter examines the growing prevalence and impact of sanctions designations on individuals, companies, and nations globally. It highlights the severe economic and personal consequences of such designations, which can lead to bankruptcy and business dissolution, often resulting in long-lasting and potentially irreparable damage. Further, the chapter critiques the process of sanctions designation as fundamentally at odds with core principles of the rule of law, particularly those central to Western legal traditions. These principles include the government’s duty to clearly articulate legal prohibitions, the necessity of providing specific accusations and supporting evidence to those penalized, the right to contest such evidence, and the availability of a meaningful appeals process. By analyzing these discrepancies, this chapter calls for a reevaluation of the sanctions framework to align it more closely with established legal norms and protections.

Chapter 13 is devoted to two important approximation methods used to solve time-independent problems, namely stationary perturbation theory and the variational method. Perturbation theory is developed for both non-degenerate states and degenerate states, with illustrative examples. The Stark effect is considered separately. The dielectric constant of a transparent medium as a function of frequency is shown to result from the modification of the wave function due to the perturbation of the radiation field. Two complementary topics are presented: the canonical transformation method and the Feynman-Hellman method. Finally, the possibilities of the variational method are illustrated by using it first to determine an upper bound for the energy of the stationary states of a quantum system, and then to study more complicated cases, including the partially shielded Coulomb potential produced by a neutral atom.

Chapter 1 explores the links between the early verse of Arthur Symons and the definitions of literary impressionism put forward in his important essay on French writing, ‘The Decadent Movement in Literature’ (1893). The chapter begins by discussing the language of sanity and wholeness (or their absence) in which the essay’s conception of impressionism is grounded, as well as its emphasis on formal fragmentation and strenuously subjective effects. It suggests that this theory furnished Symons with a rationale for his lyric experiments of the 1890s and early 1900s, which, in turn, provided models for some of the most recognisable forms of early modernist poetry. But it also draws attention to a shift in the manner and matter of Symons’s writings in the years leading up to his nervous breakdown in 1908, when a theory of literary form self-consciously preoccupied with the unstable and the fragmentary seemed to disintegrate under the pressure of its own impulse to fracture. The chapter concludes by considering the causal link Symons retrospectively drew between his conceptions of impressionism and his experience of mental instability.

Chapter 6 begins with an exposition of the WKB approximation technique developed in 1926 by Wentzel. Kramers and Brillouin. The WKB method is discussed in detail, and it is shown that it is particularly suitable when the particle is in a sufficiently energetic state that its behavior can be considered to be almost classical, for which reason it is called a semiclassical approximation. The method is applied specifically to the study of the nuclear alpha decay and the calculation of the tunneling time delay. The rest of the chapter is devoted to a discussion of the basic electronic properties of solids and some important applications of these properties, which are easily explained using the results obtained in the first part of the chapter. Starting with the free electron gas model, it concludes with a discussion of semiconductors based on the Kronig and Penney model.