The book provides a non-perturbative approach to the symmetry breaking in the standard model, in this way avoiding the critical issues which affect the standard presentations. The debated empirical meaning of global and local gauge symmetries is clarified. The absence of Goldstone bosons in the Higgs mechanism is non-perturbatively explained by the validity of Gauss laws obeyed by the currents which generate the relatedglobal gauge symmetry. The solution of the U(1) problem and the vacuum structure in quantum chromodynamics (QCD) are obtained without recourse to the problematic semiclassical instanton approximation, by rather exploiting the topology of the gauge group.
Galileo Unbound traces the journey that brought us from Galileo's law of free fall to today's geneticists measuring evolutionary drift, entangled quantum particles moving among many worlds, and our lives as trajectories traversing a health space with thousands of dimensions. Remarkably, common themes persist that predict the evolution of species as readily as the orbits of planets or the collapse of stars into black holes. This book tells the history of spaces of expanding dimension and increasing abstraction and how they continue today to give new insight into the physics of complex systems. Galileo published the first modern law of motion, the Law of Fall, that was ideal and simple, laying the foundation upon which Newton built the first theory of dynamics. Early in the twentieth century, geometry became the cause of motion rather than the result when Einstein envisioned the fabric of space-time warped by mass and energy, forcing light rays to bend past the Sun. Possibly more radical was Feynman's dilemma of quantum particles taking all paths at once — setting the stage for the modern fields of quantum field theory and quantum computing. Yet as concepts of motion have evolved, one thing has remained constant, the need to track ever more complex changes and to capture their essence, to find patterns in the chaos as we try to predict and control our world.
This book is an introduction to the concept of symmetries in electromagnetism and explicit symmetry breaking. It begins with a brief background on the origin of the concept of symmetry and its meaning in fields such as architecture, mathematics and physics. Despite the extensive developments of symmetry in these fields, it has yet to be applied to the context of classical electromagnetism and related engineering applications. This book unravels the beauty and excitement of this area to scientists and engineers.
The phenomenon of dynamical symmetry breaking (DSB) in quantum field theory is discussed in a detailed and comprehensive way. The deep connection between this phenomenon in condensed matter physics and particle physics is emphasized. The realizations of DSB in such realistic theories as quantum chromodynamics and electroweak theory are considered. Issues intimately connected with DSB such as critical phenomenona and effective lagrangian approach are also discussed.
The intriguing mechanism of spontaneous symmetry breaking is a powerful innovative idea at the basis of most of the recent developments in theoretical physics, from statistical mechanics to many-body theory to elementary particles theory; for infinitely extended systems a symmetric Hamiltonian can account for non symmetric behaviours, giving rise to non symmetric realizations of a physical system. In the first part of this book, devoted to classical field theory, such a mechanism is explained in terms of the occurrence of disjoint sectors and their stability properties and of an improved version of the Noether theorem. For infinitely extended quantum systems, discussed in the second part, the mechanism is related to the occurrence of disjoint pure phases and characterized by a symmetry breaking order parameter, for which non perturbative criteria are discussed, following Wightman, and contrasted with the standard Goldstone perturbative strategy. The Goldstone theorem is discussed with a critical look at the hypotheses that emphasizes the crucial role of the dynamical delocalization induced by the interaction range. The Higgs mechanism in local gauges is explained in terms of the Gauss law constraint on the physical states. The mathematical details are kept to the minimum required to make the book accessible to students with basic knowledge of Hilbert space structures. Much of the material has not appeared in other textbooks.
This book contains a systematic and pedagogical exposition of recent developments in particle physics and cosmology. It starts with two introductory chapters on group theory and the Dirac theory. Then it proceeds with the formulation of the Standard Model (SM) of Particle Physics, particle content and symmetries, fully exploiting the material of the first two chapters. It discusses the concept of gauge symmetries and emphasizes their role in particle physics. It then analyses the Higgs mechanism and the spontaneous symmetry breaking (SSB). It explains how the particles (gauge bosons and fermions) after the SSB acquire a mass and get admixed. The various forms of the charged currents are discussed in detail as well as how the parameters of the SM, which cannot be determined by the theory, are fixed by experiment, including the recent LHC data and the Higgs discovery. Quantum chromodynamics is discussed and various low energy approximations to it are presented. The Feynman diagrams are introduced and applied, at the level of first year graduate students.Examples are the evaluation of the decay widths of the gauge bosons and some cross sections for interesting processes such as Rutherford scattering, electron-proton scattering (elementary proton or described by a form factor, and inelastic scattering) and Compton scattering.After that the classic topics like the role of C, P, CP symmetries and the experimental methods needed to verify their conservation or violation are discussed in some detail. Topics beyond the standard model, like supersymmetry for pedestrians and grand unification, are discussed.To this end neutrino oscillations, dark matter and baryon asymmetry are also briefly discussed at the first year graduate level. Finally, the book contains an exhibition of recent developments in cosmology, especially from the elementary particle point of view.
The new edition of this well received primer on rigorous aspects of symmetry breaking presents a more detailed and thorough discussion of the mechanism of symmetry breaking in classical field theory in relation with the Noether theorem. Moreover, the link between symmetry breaking without massless Goldstone bosons in Coulomb systems and in gauge theories is made more explicit. A subject index has been added and a number of misprints have been corrected.
