Quantum Mechanics: A Fundamental Approach

The mathematical formalism of quantum theory in terms of vectors and operators in infinite-dimensional complex vector spaces is very abstract. The definitions of many mathematical quantities used do not seem to have an intuitive meaning, which makes it difficult to appreciate the mathematical formalism and understand quantum mechanics. This book provides intuition and motivation to the mathematics of quantum theory, introducing the mathematics in its simplest and familiar form, for instance, with three-dimensional vectors and operators, which can be readily understood. Feeling confident about and comfortable with the mathematics used helps readers appreciate and understand the concepts and formalism of quantum mechanics. This book is divided into four parts. Part I is a brief review of the general properties of classical and quantum systems. A general discussion of probability theory is also included which aims to help in understanding the probability theories relevant to quantum mechanics. Part II is a detailed study of the mathematics for quantum mechanics. Part III presents quantum mechanics in a series of postulates. Six groups of postulates are presented to describe orthodox quantum systems. Each statement of a postulate is supplemented with a detailed discussion. To make them easier to understand, the postulates for discrete observables are presented before those for continuous observables. Part IV presents several illustrative applications, which include harmonic and isotropic oscillators, charged particle in external magnetic fields and the Aharonov-Bohm effect. For easy reference, definitions, theorems, examples, comments, properties and results are labelled with section numbers. Various symbols and notations are adopted to distinguish different quantities explicitly and to avoid misrepresentation. Self-contained both mathematically and physically, the book is accessible to a wide readership, including astrophysicists, mathematicians and philosophers of science who are interested in the foundations of quantum mechanics.

Author Biography: K. Kong Wan is honorary reader in theoretical physics at St Andrews University, Scotland, UK. He studied theoretical physics at St Andrews, both as an undergraduate and a postgraduate, and was awarded a PhD in 1972. He stayed on at St Andrews and became a reader in theoretical physics. His research has focussed on the foundations and formalism of quantum mechanics.

Classical and quantum systems Probability theories Three-dimensional vectors and operators Matrices Generating probability distribution by self-adjoint operators and unit vectors in three dimensions N-dimensional complex vectors and operators Model theories based on N-dimensional vector spaces Hilbert spaces and operators Spectral theories for self-adjoint and unitary operators Probability, self-adjoint operators and unit vectors Physics of unitary transformation Direct sums and tensor products of Hilbert spaces and operators Quantum mechanics described by six groups of postulates Superselection rules Many-particle systems Conceptual issues Harmonic and isotropic oscillators Angular momenta Particles in static magnetic fields