Physics 115a: Quantum Mechanics

Winter 2001

Professor Jeffrey D. Richman

Broida Hall 5112, 893-8408




Quantum Mechanics

The development of quantum mechanics represents one of the greatest achievements of 20th century science, requiring a radically new theoretical framework and leading to profound technological advances. Quantum mechanics is therefore one of the most exciting subjects in the undergraduate physics curriculum, and it is perhaps the most important.

Quantum mechanics is the framework we need to understand and describe the structure of matter, and its overarching principles are essential in such fields as elementary particle physics, atomic and nuclear physics, condensed matter physics, and astrophysics. Its applications are unlimited: from nuclear magnetic resonance imaging to the devices that power computers and the Internet, quantum mechanics is an indispensable tool for understanding the most important and sophisticated technological devices and for inventing new ones.

Quantum mechanics is also one of the most important and challenging courses that you will take as an undergraduate. It involves an entirely new way of thinking about physical problems from what you have encountered in classical mechanics, electromagnetism, and thermodynamics. In each of these branches of physics, there are startling examples where the classical (i.e., non-quantum) predictions fail completely to describe the observed phenomena. These observations cannot be accounted for by minor changes to classical theories; an entirely new and conceptually different set of physical principles is needed.


Goals of This Class

This class (Ph 115a) has several goals:

In Ph 115b and 115c, we will study many other quantum systems.

How to Succeed in This Class

Richard Feynman once said that learning quantum mechanics is like painting a house: you need more that one coat of paint. After taking this course, you will almost certainly feel that there are many aspects of quantum mechanics that you do not understand well. Because quantum mechanics is such a strange, deep, and complex subject, you could study it for a lifetime. The course that I will teach is mainly a non-relativistic treatment; in graduate school, you typically take a more sophisticated version of the same thing, and then move on to relativistic quantum mechanics and relativistic quantum field theory. Eventually, you may even study string theory, which promises to solve one of the greatest problems of physics: how to combine quantum mechanics and gravity.

Quantum mechanics may be one of the most difficult courses you will take as an undergraduate, and it will require a high level of discipline and effort to master it. The rewards, of course, are enormous: you will have learned the language required to understand much of modern physics.

Here are some specific suggestions on how to do well in Ph 115:



Grades, Homework, Tests, and All That Stuff

  1. Homework: 40%
  2. Midterm: 25%
  3. Final exam: 35%


Books on Reserve

I have put a number of books in the Reserve Book Room of the Davidson Library. There is a broad range in the style of presentation, and you may find some much more helpful than others.

  1. C. Cohen-Tannoudji, B. Diu, F. Laloe, Quantum Mechanics, Vols. I and II. An impressive book; rather long but extremely detailed. Often used as a textbook.
  2. R. Liboff, Introductory Quantum Mechanics. Used in last-yearís course as textbook; a good book.
  3. A. Goswami. Quantum Mechanics. I havenít read it, but some people think highly of it.
  4. D. Griffiths, Introduction to Quantum Mechanics. By a prolific textbook writer; used at many universitites. Some students complain that it does not have enough information and can be confusing.
  5. A. Messiah, Quantum Mechanics, Vols. I and II. A classic, somewhat advanced treatment.
  6. D.T. Gillespie, A Quantum Mechanics Primer. Short and easy. Helpful if you are totally confused.
  7. L. Landau, Quantum Mechanics. A classic; difficult.
  8. M. Morrsion, Understanding Quantum Physics. I havenít read it.
  9. A. Migdal, Qualitative Methods in Quantum Theory. A very interesting book, with many physical examples and ingenious methods for solving them. Probably best appreciated after a quarter or two of quantum mechanics.
  10. J. Singh, Quantum Mechanics. A perspective from an expert on technological applications.
  11. G. Gamow, Thirty Years that Shook Physics. An amusing historical book, with photographs of Bohr riding a motorcycle, Heisenberg in a bathing suit, and Fermi playing tennis.
  12. D. Park, Introduction to the Quantum Theory. An old standby. I havenít read it.
  13. A. Yariv, An Introduction to the Theory and Applications of Quantum Mechanics. A perspective from a famous laser physicist.
  14. P. Landshoff, A. Metherell, G. Rees, Essential Quantum Physics. A short book with some physical examples. Supplemental text for this course.
  15. H. Ohanian, Principles of Quantum Mechanics. I havenít read it.
  16. E. Taylor and J. Wheeler, Spacetime Physics. A great book to brush up on your special relativity or to learn it for the first time. Very pedagogical and interesting.




Ph 115a: Preliminary Schedule for Winter 2001




Chapters (Shankar=S/Landshoff=L)


Mon, Jan 8

Mathematical Introduction



Weds, Jan 10

Math Intro



Mon, Jan 15

MLK Holiday



Weds, Jan 17

Math Intro



Fri, Jan 19

Math Intro



Mon, Jan 22

Math Intro;

Classical Mechanics and its Limitations




Weds, Jan 24

Evidence for Quantum Behavior



Mon, Jan 29

Postulates of Quantum Mechanics



Weds, Jan 31

Postulates of QM



Mon, Feb 5

Postulates of QM



Weds, Feb 7

Problems in One Dimension



Fri, Feb 9

Problems in One Dimension



Mon, Feb 12

Problems in One Dimension



Weds, Feb 14



Mon, Feb 19

Presidentsí Day Holiday



Weds, Feb 21

Problems in One Dimension



Mon, Feb 26

The Classical Limit



Weds, Feb 28

Quantum Harmonic Oscillator



Mon, Mar 5

Q. Harmonic Oscillator



Weds, Mar 7

Q. Harmonic Oscillator



Mon, Mar 12

Q. Harmonic Oscillator



Weds, Mar 14

Q. HarmonicOscillator



Note: classes 4.5 and 12.5 are particularly important recitation sections.