Lorentz symmetry is at the core of modern physics: the kinematical laws of special relativity and Maxwell’s field equations in the theory of electromagnetism respect it. The direct relativistic extension of the Schrödinger equation leads to the Klein–Gordon equation, which will be interpreted in the context of the second quantization, to describe bosons. In the Standard Model all interactions are induced by intermediate vector gauge boson fields and the Higgs boson is represented by a scalar boson field.

The areas discussed in this chapter are distinct in modern legal systems but in Roman law they overlap or shade into one another. The first is crime; the second delict (or ‘tort’ as it is called in some modern systems); and the third the maintenance of public order through regulation and policing.

Chapter 1 dealt with the main sources of Roman private law, in the sense of the formal sources that created it. This chapter is about the use of Roman legal sources by the modern student or scholar. It gives an account of those sources and problems that arise in using them. Nearly all the surviving material of Roman law is transmitted in one or other of the Emperor Justinian’s compilations. The chapter begins with an account of the sources that survive independently of Justinian; it then moves on to the Digest and (very briefly) other parts of the Justinianic compilations. It concludes with a general discussion of the difficulties of trying to write history based on legal sources.

Hadrons are copiously produced at high-energy electron–positron or hadron–hadron colliders and provide a well-suited environment to study QCD. Electron–positron colliders are particularly well suited, since the tree-level process is the 𝑠-channel annihilation into a virtual photon and a quark–antiquark pair in the final state.

When we first observe the Universe, it might appear to us as a very complex object. One of the primary goals of the philosophy of Nature (or simply Physics) is to “reduce” (“simplify”) this picture in order to find out what the most fundamental constituents of matter (i.e., the atoms from the Greek word indivisible) are and to understand the basic forces by which they interact in the otherwise void space, along the line of thinking of Demokritos who wrote “Nothing exists except atoms and empty space.”

This chapter deals with the main legal issues that arise in connexion with Roman commerce: contract in general; the main commercial contracts: sale, contracts of loan and for security; and contracts for services, such as carriage of goods and building contracts. It then moves on to deal with how Roman businesses may have been organized: what sort of labour they used; and how they attempted to limit their liability. It concludes with the law of insolvency.

The weak force acts among all elementary fermions, that is, all leptons (𝑒, 𝜇, 𝜏, 𝜈) and all quarks (𝑢, 𝑑, 𝑠, …).

Particle accelerators are devices that produce different kinds of energetic, high-intensity beams of stable particles (𝑒, 𝑝, …). They possess many fields of application: nuclear and particle physics, material science, chemistry, biology, medicine, isotope production, medical imaging, medical treatments – just to name a few. Beams of accelerated primary particles can be used to produce beams of secondary metastable particles, such as 𝜇’s, 𝜋’s, 𝐾’s, etc

The Poincaré group and its Lorentz subgroup are of great importance because invariance under the Poincaré group is a fundamental symmetry in particle physics. For example, a relativistic quantum field theory must have a Poincaré-invariant Lagrangian. This means that its fields must transform under representations of the Poincaré group and Poincaré invariance must be implemented. Here we will discuss some properties of the Lorentz and Poincaré groups.