Foreword

Students who study Quantum Mechanics for the first time encounter difficult concepts which are new and are unfamiliar. Quantum Mechanics is the mechanics at the atomic and subatomic scale. Therefore, any book on quantum mechanics for beginners has to make this clear that for description of microscopic objects a Mechanics different from Classical Mechanics is needed. Dr Ishwar Singh Tyagi has done this admirably in this book titled Principles of Quantum Mechanics.

In the initial chapters of the book, the basic concepts of quantum mechanics are introduced in a logical and simple manner followed by the chapters which present the solution of the Schrodinger equation for situations where it is exactly solvable. After this comes a discussion of approximation methods for solving Schrodinger equation when exact solutions are not available. A distinguishing feature of this book is a readable and simple exposition of theory of measurement in quantum mechanics, as well as the emerging field of quantum computing. I also appreciate that at the end of each chapter a number of exercises with solutions are given. I recommend students to try solving these problems themselves (without looking at the solutions given), so that they get a deeper understanding of concepts and acquire mathematical skills to apply quantum mechanics to various physical systems.

Dr Ishwar Singh is a reputed teacher and researcher. I have the privilege of knowing him for the last four decades. His dedication to research and teaching has been exemplary. His research interest lie in strongly correlated electrons in the condensed matter and the theory of measurement in quantum mechanics. When I was at the University of Roorkee (now IIT Roorkee) from late sixties to mid eighties, I enjoyed my discussions with him on numerous physics problems. He always tries to understand a physical problem from first principles. I was always impressed by his ability to present a topic in a simple and elegant manner.

I found this book to be an excellent introduction to the subject. I am sure students will enjoy learning quantum mechanics from this book. This will be an ideal book for B.Sc. and M.Sc. students in our universities. Dr Ishwar Singh deserves our praise for this effort.

Professor S. K. Joshi
(Ex D.G., CSIR, New Delhi)