Reprint of the Preface to Lectures on Quantum Mechanics

Quantum theory is, perhaps, the most precisely tested and most successful theory in the history of science, which brought in great impact on our world. Quantum mechanics is one of the fundamental building-blocks of physics. It not only affects the way we think about the universe profoundly, but also constitutes a basis for much of condensed-matter, nuclear and statistical physics effectively. It also has a strong influence on modern technological developments, for instance, in optical and electronic devices. It is also expected to help the development of spintronics or to put a quantum computer into practice.

This book is designed to serve as a textbook rather than as a mono-graph. All the material in this book is based on lecture courses given by the author to third-year undergraduates in Physics Department, Zhejiang University since 2002. The course is provided for undergraduates who have the knowledge of atomic physics and are available at mathematical methods such as calculus, linear algebra, partial differential equations as well as special functions. In order to help students keep the pace with the key clue without being overwhelmed by heavy mathematical formulation,several mathematical contents that are frequently referred in the course are given as appendices. Unless they are inevitable, new postulates and concepts are attempted to be introduced as slow as possible during the progress of the course. This is based on the author's following two princi-ples: (i)if a textbook were so perfectly arranged that leaves nothing to be desired, it would make the readers feel that the scientific discovery is so mystical that they lose passion of creativity; (ii)if a course were so purely presented that is high on a perfect axiomatics without mention of incom-plete doctrine in history of science, it would lose the chance of training students'power of creativity. College students should cultivate their abili-ty of capturing knowledge and attain the power of employing knowledge in addition to the simple task of absorbing knowledge. So the author tried to adopt second-person pronoun in presenting this course. According to the author's teaching experience, some mediate steps of mathematical formu-lation that beginners are not able to figure out frequently, are also given. In order to avoid too much content in class, some important examples are arranged as problems with solutions.

There is a saying that“physics can not be learnt by merely listening and reading, but by writing, thinking and worrying”. Niels Bohr tipped off that anyone who were not shocked by quantum theory had not understood a single word. Willis Lamb addressed that anyone wanting to discuss a quantum mechanical problem had better understand and learn to apply quantum mechanics to that problem. Thus, the students are highly sug-gested to rethink the newly introduced concepts, to follow the necessary formulations, and to carry out the selected exercises outside class, which will benefit students most. Besides the selected problems for each chapter, several additional problems that require students' aggregative knowledge of the whole course are given after the last chapter.

Youquan Li

Hangzhou,2010