This online book is written at two levels: Elementary-level material is written in this Arial font with a blue bar at left. It is written at the "intelligent layman" level of Scientific American and uses few equations and many pictures. The prerequisite for understanding these sections of the book is a college-level course in modern physics at the freshman or sophomore level. It might be accessible to someone who has read a few popular books on quantum mechanics.

Advanced-level material is written in this Times font in plain black and white. It is written at the level of an American Journal of Physics article or a first-year-graduate physics text and uses equations liberally. The prerequisite for understanding these sections of the book is an upper-level-undergrad course in quantum mechanics.

The reason for this two-level system is my belief that physics, and in particular quantum mechanics, can be taught at multiple levels using the same concepts. I want to show the connection between an intuitive, pictorial understanding and a mathematical understanding. Both are very important, in my view, and I think that students can learn what a calculation will accomplish without necessarily knowing how to do the calculation. In that spirit, the elementary sections will present lots of mechanical analogies for what quantum mechanics is calculating. I will usually try to show some sort of graph or physical model of these. Note that many of these pictures are animated, indicated by "(Mouse over to see animation.)" in the caption. To animate such a picture, place your cursor somewhere over it (called "mousing over" the image) and it should begin to move. The picture below illustrates this. Figure 1: Graphs of a propagating coherent wave (chapter 3). (Mouse-over to see animation.)

The advanced sections serve at least two purposes, (1) to connect the physcial pictures from the elementary sections to the calculations found in graduate-level textbooks on the subject, and (2) to introduce the topic of quantum field theory (QFT) at a level between the too-simple undergrad books and the too-advanced grad books. That is, this is to be the introduction to QFT that I wish I had when I first studied the subject.

Unfortunlately as of yet, there is no good way to put mathematical expressions on web pages, so I have decided to use GIF images of equations typeset by LaTeX. Here is an example, the Schrodinger equation:

(0.1)

Note that you can adjust the size of the text on all these pages using your browser's text size option (in Microsoft Internet Explorer, it is under View > Text Size), but that the equations will remain fixed in size. The pages default to a large text size so that subscripts and superscripts, like q_i^† |0>, are readable (and for readers with reduced eyesight).

I hope you find this online book useful in your studies, whether you are a physics student or a curious non-physicist. Please feel free to contact me at Scott@VisualQuantum.net to make suggestions, comments, or to ask questions.

Scott Johnson,   2009