Q&A: A. Zee on explaining physics to any audience

Books on group theory, the branch of mathematics dealing with the properties of sets, have long struggled to find a balance between mathematical theory and physical insight, says theoretical physicist Piet Van Isacker in the January issue of Physics Today. Luckily for physicists, there is now a book that provides both: A. Zee’s Group Theory in a Nutshell for Physicists (Princeton University Press, 2016), which Van Isacker dubs “a tour de force that guides readers through the universe of group theory.”

Zee’s success will come as little surprise to those familiar with his work. The theorist from the University of California, Santa Barbara , is an accomplished author of both textbooks and popularizations. He has written on everything from quantum field theory to Chinese language and cuisine.

Physics Today recently caught up by email with Zee—who is currently on sabbatical in Paris—to talk about writing, reading, and what’s next for physics.

PT: In your previous Nutshell textbook, Einstein Gravity in a Nutshell, you wrote about “the importance of feeling amazed and amused” when studying physics. What do you think readers will find amazing and amusing about group theory?

ZEE: Ah, group theory! The entire subject is amazing and amusing. Who would have expected that three Platonic solids—the cube, tetrahedron, and icosahedron—would pop up in constructing the Dynkin diagrams of the exceptional Lie algebras ? Or that finite group theory could determine the remainder when 10¹⁰ is divided by 11?

PT: You’ve written books aimed at a range of audiences. What do you enjoy most about the process? What do you find the most challenging?

ZEE: Popular books on physics and physics textbooks present different challenges. I feel that in the end I enjoy writing textbooks a bit more because the aim is to transmit enjoyment and knowledge to a new generation of physicists, just as that enjoyment and knowledge have been transmitted to me. That, in essence, is what physics is all about. I think I expressed that in the prefaces to more than one of my textbooks. During a visit to Austin, Texas, in the early 1980s, I told [Nobel laureate] Steve Weinberg that I was thinking of turning the notes for my field theory courses into a book. At that point I had produced only Unity of Forces in the Universe, and that only half counted as a book. Weinberg said, “Write a popular book first as preparation for writing a textbook.” The result was Fearful Symmetry (1986), which is still going strong after all these years. I hope the result of that excellent advice shows in my textbooks.

PT: Your book Swallowing Clouds: A Playful Journey Through Chinese Culture, Language, and Cuisine gives readers a lesson in how to read and appreciate a Chinese menu. Did the experience of writing the book influence how you think about physics or physics teaching?

ZEE: To the contrary! I jokingly told my physicist friends that Swallowing Clouds allowed me to get away from them. It was entertaining to be invited to conferences of food professionals and to meet various luminaries in another universe. Shortly after starting the book, I was invited to spend some time at the Chinese University of Hong Kong as a visiting scholar, and the book gave me a license to explore the fabulous world of cuisine in Hong Kong.

PT: It has been an eventful few years for physics, with the detection of gravitational waves and the discovery of the Higgs boson confirming earlier theoretical predictions. What do you see on the horizon that most excites you?

ZEE: I am most excited by the prospects of learning more about the dark world of energy and matter, and of experimentalists coming up with clever new approaches. Just recently I dropped in on an atomic physics conference in Paris. I learned from the lecture of Jun Ye of the University of Colorado Boulder about the possibility of detecting a passing gravitational wave by an array of atomic clocks that experience the passage of time differently.

PT: What is your next project?

ZEE: I am struggling to finish a short popular book on Einstein gravity. I was a bit stung by a reader on Amazon who, while he liked my gravity textbook, jokingly said that he had to ask a friend to carry it for him. (What a weakling! Don’t physics students go to the gym anymore? Bring back the compulsory gym of my undergrad years!) Actually, it weighs less than the textbook by Misner, Thorne, and Wheeler. Anyway, my editor at Princeton University Press challenged me to write a short book for a change. A week after I signed the contract, gravitational-wave detection was announced. I thought I could finish the book before moving to Paris, but that proved to be unrealistic.

PT: What books are you currently reading?

ZEE: In Santa Barbara I was finishing Julian Barnes’s witty and profound Nothing to Be Frightened Of, but now I have far too many things going on in Paris to have time to worry about nothing. Meanwhile, on the recommendation of several French friends, including two theoretical physicists, I have started the novel Le dit de Tianyi by François Cheng. If I ever get through Cheng’s novel, I should try his Five Meditations on Death: In Other Words . . . On Life to find out how, or whether, he differs from Barnes.