Many-particle systems play a fundamental role in physics where we encounter systems of molecules or systems of elementary particles in quantum field theory. Many-particle theories provide the basis for understanding the macroscopic behaviour of vast assemblies of interacting particles starting from their microscopic properties and leads to descriptions of entropy, statistical mechanics and fluid mechanics. Covering a wide range of topics and including more than 400 problems and solutions, this book is an ideal resource for students specialising in many-particle systems. Key features • Several hundred problems with solutions in each volume. • Problems range from basic introductory to advanced level. • Features worked examples as well as solutions to many problems. • Includes key concepts. • Covers essential complete physics course.
Abstract This essay aims to show how adoption of a pragmatist interpretation permits a satisfactory resolution of the quantum measurement problem. The classic measurement problem dissolves once one recognizes that it is not the function of a quantum state to describe or represent the behavior of a quantum system. The residual problem of when, and to what, to apply the Born Rule may then be resolved by judicious appeal to decoherence. This can give sense to talk of measurements of photons and other particles in applications of quantum field theory. A quantum field theory does not describe a physical system to which it is applied as containing particles or fields. But pragmatist inferentialism shows when one may talk of particles or of fields when describing outcomes of measurements on systems to which a quantum field theory is applied.