Library of Science interview concerning
The Strange World of Quantum Mechanics

This World Wide Web page written by Dan Styer, Oberlin College Physics Department;
http://www.oberlin.edu/physics/dstyer/StrangeQM/;
last updated 29 March 2000.


Interview of Dan Styer, author of "The Strange World of Quantum Mechanics"
by Dara Amchin of the Library of Science Book Club

9 March 2000


Question 1: The Library of Science Book Club is pleased to feature "The Strange World of Quantum Mechanics" as an alternate selection for the month of April. Please tell me, when did you first know that you wanted to study quantum mechanics?

Answer 1: As a teenager I read popular books by Isaac Asimov that ranged over the entire domain of science. From these I found that quantum mechanics undergirds our entire understanding of the natural world -- atoms, molecules, DNA, transistors, computer chips, stars. I knew then that I wanted to study the powerful techniques of quantum mechanics. At the same time, I knew that I wanted to be more than just a technician, so I wanted to tackle the concepts of quantum mechanics as well.


Question 2: Quantum mechanics is often considered a detailed technical subject valuable only to specialists. Why should an average person be concerned about quantum mechanics?

Answer 2: For two reasons. First, quantum mechanics is incredibly bizarre and therefore extremely fascinating. No author of fantasy fiction ever invented an imaginary world as strange and mesmerizing and wonderful as our own world, the world of quantum mechanics.

Second, our discovery of this bizarre face of our own world demonstrates remarkably the power of reason and logic as tools for probing the unknown. When you enter the strange world of quantum mechanics, common sense fails as a guide. But you can still illuminate this strange world using your own power of reason. In today's world, where slick public relations and brutal power play have largely displaced reason in the domain of public discourse, I cling to this success of reason as a ray of hope.


Question 3: "The Strange World of Quantum Mechanics" came about as a result of your lectures at Oberlin College. What was it like, the process of writing this book?

Answer 3: When I started teaching my course on quantum mechanics for a general audience (that is, as opposed to a technical course for physics and chemistry majors), my plan was simple: I would cover the material from the first three weeks of my technical course, but I would present the arguments very slowly and carefully so that my new students, who were not proficient in mathematics, would be able to follow every step and hence be just as convinced as my technical students were.

This proved to be a disaster. I will never forget the day when I derived an important result, a student raised his hand to say he didn't understand, and I presented the same derivation again, but slower. The student replied that he had followed the derivation the first time, but that to him it wasn't a convincing argument, it was just "a bunch of mathematical gobbledygook." That was when it hit me full force that my general audience students were not just like my technical students, except with a lesser mathematical background. They were just as interested in a deep, rigorous understanding of the subject, but they had different ideas about what "understanding" meant.

After teaching the course a few times, I had to agree with them. I found myself simply unable to answer some of the questions poised by my students. These were good questions, reasonable questions, but they were not the sort of questions that physicists tend to ask. I had been so well trained in the thought patterns of a physicist that I never would have raised such questions myself.

So I went back to the beginning and rethought all of my own understanding of quantum mechanics, trying to get much deeper than "this is what comes out of the equations." I was fortunate to do this at a time when the foundations of quantum mechanics were being confirmed by extraordinary experiments that probed the theory at its most vulnerable points; at a time when professional debate on the meaning and understanding of quantum mechanics was rising after a long period of artificial silence; and at a time when quantum weirdness was being explored as a practical tool for building a whole new class of computers and of private codes. The book is the result of my rethinking.


Question 4: How much input did your students give?

Answer 4: One year, I gave out a draft version of my book and told the students to react to their assigned reading through written "reading memos," where they told me what they were thinking about, which parts were tough, where the argument was shaky or unconvincing (not to mention which words I had misspelled). That was a big help, but an even bigger help was just listening to their questions and their reactions in class. They brought different backgrounds, different expectations, and different needs to the course, and it delighted me to see my old friend, quantum mechanics, look so different and fresh through their eyes.


Question 5: Who are your scientific heroes?

Answer 5: I'll have to follow the herd here and point to Albert Einstein. He was (particularly in his younger years) willing to go wherever his investigations led him, no matter how weird or unfamiliar the landscape became. He had very good mathematical technique, but he also insisted on deeper understanding. He has been criticized for refusing to adopt quantum mechanics as a fundamental theory, but his objections to quantum theory ultimately led to the convincing experiments that, as I said earlier, "probed the theory at its most vulnerable points."


Question 6: What would you like to accomplish in your work that you haven't done already? What's your next project?

Answer 6: At first glance, quantum mechanics seems weird or even, perhaps, grotesque. The same is true at second glance. But after you've looked at it for long enough, and after you've digested the experiments and reasoning that undergird our understanding, then phenomena like interference and entanglement become almost second-nature. At that point the question becomes not, "Why is quantum mechanics so strange?" but rather, "Since interference and entanglement do exist in our world, why don't we usually notice them?" In other words, it raises the question of the classical limit of quantum mechanics. I'm currently studying this highly technical topic. It has a wonderful character that I liken to nesting Russian dolls: You think up a problem and find an initial solution. But if you examine that solution in detail, you find that you've missed something and can further deepen your understanding with a different approach. Your initial solution is still correct, but your second solution is deeper and more beautiful. But on examining the second solution, you find that it can again be deepened. And so forth.

Another project involves Einstein's theory of relativity. When this topic is taught to physics majors, a central role is played by the four equations of the Lorentz transformation. For many years, I thought this was the only honest way to teach relativity. However, after teaching relativity to general audience students, I found to my horror that I was using the Lorentz transformation equations as a formal tool to answer problems even when I didn't understand what was going on. Rather than being "central to my understanding," I was using the Lorentz transformation to avoid understanding! I am recasting my approach to teaching relativity with this lesson in mind. (The Lorentz transformation equations are still necessary for efficient problem solving, and physics majors must master them. Yet no one should use them as I did -- as a crutch to avoid understanding.)


Question 7: What would you do if you couldn't be a scientist?

Answer 7: If I couldn't be a scientist, I would do something with an outdoor slant: wilderness guide, perhaps, or farmer, or forest ranger. I would enjoy these professions because they afford daily contact with the beauty of nature. The great thing about being a physicist is that I have daily contact with the beauty of nature both in its surface aspects (diffraction patterns, soap-bubble rainbows, crystals) and in its deeper, structural aspects (wave nature of light, interference, arrangement of atoms in crystals).


Question 8: Is there anything you'd like to add?

Answer 8: As I said at the beginning, I was originally attracted to quantum mechanics through the popular writings of Isaac Asimov. I liked Asimov's work (I still do) but one facet of it disturbs me deeply. His approach was to simply tell his readers what the facts and ideas were, and his readers just had to accept them. But accepting something on the basis of authority is the very antithesis of scientific thinking. In "The Strange World of Quantum Mechanics," I present the experiments and reasoning behind the facts and ideas so that readers can decide for themselves, not just accept what I say.