Quantum Field Theory as Simply as Possible

5.0 out of 5 stars Tired of popularizations? Buy this book.

The following is my review published in Amazon — the other 25 reviews are interesting and somewhat divergent– here’s a link to them all — https://www.amazon.com/Quantum-Field-Theory-Simply-Possible/dp/0691174296#customerReviews.

 

 

I’ve put in two further thoughts I left out to keep the Amazon review to a reasonable length (Addendums 1 and 2).

 

Disclaimer: I have probably spent more time with Quantum Field Theory As Simply As Possible (QFTASAP) than most as I was a lay reader providing commentary to Dr. Zee as he was writing it. I came to know Dr. Zee after he responded to some questions I had while going through another of his books, Group Theory in a Nutshell for Physicists. We’ve corresponded for years about math, physics, medicine, biology and life both turning out to be grumpy old Princeton Alums (1960 and 1966). If this makes me a friend of his despite never having met and living on opposite coasts — and if this precludes this review appearing on Amazon, so be it.

Should you buy the book? It depends on two things: (1) your ability and (2) your background. Dr. Zee spends a lot of time in the preface describing the rather diverse collection of people he is writing for. “I am particularly solicitous of the young, the future physicists of the world. .. delighted beyond words if some college students, or even a few high school students are inspired by this book .. “

Addendum 1  In retirement, I met one such high school student whil auditing an abstract algebra course at a local college.  He was simultaneously doing his German homework while listening to the lecture with one ear.  He did not go on in physics but did get a double summa in math and physics at an Ivy League university (not Princeton despite my attempts to get him to go there).

 

I fall into another class of reader for QFTASAP which the author mentions, “scientists, engineers, medical doctors, lawyers and other professionals . … Quite a few are brave enough to tackle my textbooks. I applaud these older readers, and address them as I write.”

So you need to know the background I bring to the book to put what I say in perspective. I am a retired neurologist. I did two years of graduate work in chemistry ’60 – ’62 before going to medical school. All grad students in chemistry back then took quantum mechanics, solving the Schrodinger equation to see where atomic (and molecular orbitals) come from.

At my 50th reunion, I met a classmate I didn’t know as an undergraduate, Jim Hartle, a world class relativist still writing papers with Hawking, so I decided to try and learn relativity so I’d have something intelligent to say to him if we met at another reunion. I studied his book on Gravitation (and Dr. Zee’s). Unfortunately COVID19 has stopped my attendance at reunions. To even begin to understand gravitation (which is what general relativity is about), you must first study special relativity. So my background was perfect for QFTASAP, as quantum field theory (QFT) tries to merge special (not general) relativity and quantum mechanics.

Do not despair if you have neither background as Dr. Zee starts the book explaining both in the first 99 pages or so. His style is very informal, with jokes, historical asides, and blinding clarity. As a retired MD I can’t speak to how accurate any of it is, but the publisher notes that his textbooks have been used at MIT and Cal Tech, which is good enough for me.

So quantum mechanics and special relativity gets you to base camp for the intellectual ascent to QFT — which takes the rest of the book (to page 342). If this sounds daunting, remember thAt physics majors and physics grad student’s QFT courses last a year (according to Dr. Zee). So read a little bit at a time.

The big leap (for me) was essentially abandoning the idea of force and thinking about action (which was totally unfamiliar). Much of the math, as a result is rather unfamiliar, and even if you took calculus, the integrals you will meet look like nothing you’ve ever seen.
e.g. d^4x e psibar (x) gamma^mu psi(x) A_mu(x) all under the integral sign
Fortunately, on p. 154 Dr. Zee says “I have to pause to teach you how to read this hieroglyphic.” This is very typical of his informal and friendly teaching style.

QFTASAP contains all sorts of gems which deepened my understanding of stuff I’d studied before. For example, Dr. Zee shows how special relativity demolishes the notion of simultaneity, then he goes even farther and explains how this implies the existence of antiparticles. Once you get integrals like the above under your belt, he gives a coherent explanation of where and how the idea of the expanding universe comes from and how it looks mathematically.

There is much, much more: gauge theory, Yang Mills, the standard model of particle physics etc. etc.

To a Princetonian, some of the asides are fascinating. One in particular tells you why you or your kid should want to go there (spoiler alert — not to meet the scion of a wealthy family, or an heiress, not to form connections which will help you in your career). He mentions that there was an evening seminar for physics majors given by a young faculty member (33) about recent discoveries in physics. In 1964 the same young prof (James Cronin) said that he had discovered something exiting — in 1980 he got the Nobel for it. For my part, it was John Wheeler (he of the black hole, wormholes etc) teaching premeds and engineers (not future physicists) freshman physics and bringing in Neils Bohr to talk to us. So go to Princeton for the incredible education you will get, and the way Princeton exposes their undergraduates to their very best faculty.

Addendum #2 — As a Princeton chemistry major, my undergraduate adviser was Paul  Schleyer , Princeton ’52, Harvard PhD ’56. We spent a lot of time together in his lab, and would sometimes go out for pizza after finishing up in the lab of an evening. For what working with him was like please see — https://luysii.wordpress.com/2014/12/15/paul-schleyer-1930-2014-a-remembrance/ and https://luysii.wordpress.com/2014/12/14/paul-schleyer-1930-2014-r-i-p/

Contrast this with Harvard where I did chemistry graduate work from ’60 – ’62.   None of the 7 people who were in the department back then who later won the Nobel prize later (Woodward, Corey, Hoffmann, +4 more) did any undergraduate teaching.  I did most of the personal teaching the Harvard undergrads got — 6 hours a week as a teaching assistant in the organic chemistry lab.  I may have been good, but I was nowhere as good as I would be if I stayed in the field for 8 more years.   I thought the Harvard students were basically cheated. 

I guess every review should have a quibble, and I do; but it’s with the publisher, not Dr. Zee. The whole book is one mass of related concepts and is filled with forward and backward references to text, figures and diagrams. Having a page to go to instead of Chapter III, 1 or figure IV.3.2 would make reading much easier. Only the publisher could do this once the entire text has been laid out.

One further point. QFTASAP clarified for me the differences between the (substantial) difficulties of medicine and the (substantial) difficulties of theoretical physics. When learning medicine you are exposed to thousands of unrelated (because we don’t understand what lies behind them) facts. That’s OK because you don’t need to remember all of them. Ask the smartest internist you know to name the 12 cranial nerves or the 8 bones of the wrist. The facts of theoretical physics are far fewer, but you must remember, internalize and use them — that’s why QFTASAP contains all these forward and backward references.

There is a ton more to say about the book and I plan to write more as I go through the book again. If interested, just Google Chemiotics II now and then. QFTASAP is definitely worth reading more than once.

 

Helpful

Paul Schleyer (1930 – 2014) R. I. P.

This is a guest post by Peter J. Reilly, Anson Marston Distinguished Professor Emeritus, Department of Chemical and Biological Engineering, Iowa State University, fellow Schleyer undergraduate advisee Princeton 1958 – 1960, friend, and all around good guy.

I’ll follow with my own reminiscences in another post. Obits tend to be polished and bland, ‘speak no evil of the dead’ and all that, but Peter captures the flavor of what it was actually like to be Paul’s advisee and exposed to his formidable presence.

“Following are my thoughts on our undergraduate chemistry advisor at Princeton, Paul von Ragué Schleyer, who died on November 21 of this year at 84.

Paul was an amazingly prolific chemist. He started publishing in 1956, soon after he arrived at Princeton from receiving a Ph.D. at Harvard, where he studied from 1951 to 1954 after earning an A.B. from Princeton. He was still publishing at the time of his death. In fact, he had promised to deliver a book chapter over this Thanksgiving weekend. Over his latter years at Princeton, in the early 1970’s, his annual production of papers averaged the middle 20’s. He kept up the same pace at Universität Erlangen-Nürnberg in Germany from 1976 to 1992. From 1993 to 1997, when he had appointments at both Erlangen-Nürnberg and the University of Georgia, he was in the 40’s. When fully at Georgia, after 1997, he gradually slacked off, publishing only 16 papers this year. Altogether he had 1277 publications, when a really productive chemist with ready access to students and postdoctoral fellows hopes to have 200–250 in a full career.

Another way to consider Paul’s productivity is by how often his work had been cited (partly by his own later papers but mainly by the papers of others). A 1981–1997 survey reported that he was the third most cited chemist in the world. Althogether his works were cited over 75,000 times. His h-index is 126 in the Thomson Reuters Web of Science database, meaning that he had 126 publications that were cited at least 126 times, an astounding number.

I first met Paul in the fall of 1958, two years after I arrived at Princeton. I needed to find someone to supervise my junior paper, a ritual common to all Princeton undergraduates doing A.B. degrees. I had originally approached Edward Taylor, a somewhat older chemistry professor, but when I told him that I was somewhat interested in becoming a chemical engineer, he directed me to Paul. Paul was 28 at the time, but he seemed older to me (I supposed all professors did). He was tall, with dark black hair combed to the side over his forehead. He had a scar on his cheek and talked very precisely.

My father met him once and came away asking if he had been a German U-boat captain during WWII.

I must say that I spent a sizable part of the next two years being terrified of Paul. He had a laboratory in the second floor of the southwest corner of Frick Chemical Laboratory. The benches were full of glassware, to the point where it seemed hard to do any research. However, the item that spooked me the most was a cauldron full of boiling black liquid, supposedly mainly nitric acid, in which dirty glassware was submerged to be cleaned.

Paul gave me a project to research the incidence and properties of the benzyne intermediate, a short-lived benzene ring with a triple bond. This was my first exposure to research beyond short papers for classes, and I suppose that I did well enough for him to invite me to do a senior thesis with him. The topic was to determine the mechanism by which an obscure organic chemical rearranged itself. The title of the thesis that came from a year’s dogged effort was “A Study of the Cleavage Products of 2,5-Dimethyltetrahydropyran-2-Methanol”, but what I mainly made was black goop. Paul’s written comments to me started with the statement that he was sorry that the problem was so intractable, but at least he liked my writeup. I still have the thesis (and the junior paper). Back in 2007 I was contacted by the Princeton University Library, which had lost its copy. They asked if I could send them mine so that they could microfilm it, which of course I did.

I remember that at least four of us chemistry majors spent much of our senior years in a very large and empty laboratory working on our theses under Paul’s direction. I must say that the various chemicals that I worked on smelled a lot better than the ones that you dealt with. I used to take weekend dates up to the laboratory to show them where I worked, and I would open one of your very small tubules, I think containing butyl mercaptan. Its smell still permeated the room on Mondays. (Editor’s note — people used to look at their shoes when I walked into the eating club after working with n-Bu-SH or similar compounds).

Despite my lack of success on my thesis, I learned from it how to do research. My chemical engineering major professor at the University of Pennsylvania was hard to contact, so much of my doctoral dissertation was done without much supervision. Between the two experiences, I had a good foundation for my 46 years of being a chemical engineering professor, six at the University of Nebraska-Lincoln and 40 at Iowa State University after four years at DuPont in southern New Jersey.

I only saw Paul four times after leaving Princeton. The first was when I returned there for a short visit. The second time was at my 25th Princeton reunion, when one of his daughters was graduating. A third time was when he visited the Iowa State chemistry department to present a prestigious lecture. The fourth and last time was in 2005 when I visited the University of Georgia for a meeting. Paul spent about 30 minutes telling me about his latest research, of which I understood very little.

I will close with a little story. When I told Paul during my senior year that I wanted to go to graduate school in chemical engineering, he asked why I wanted to become a pipe-fitter. Probably because of my chemistry background at Princeton, my research was always chemistry- and biology-based, first in fermentations at Penn and Nebraska (with a detour to chloro- and fluorocarbons at DuPont), and then in enzymes and carbohydrates at Iowa State. I moved more and more into computation late in my career, and when Paul visited around 2002 I told him that I would be sending a manuscript to the Journal of Computational Chemistry, which he and Lou Allinger at Georgia had founded and were still editing. Being Paul, he immediately said in his deep voice that it had better be good. As it turned out, it sailed through the review process with hardly a blip, and I followed it up with a second manuscript a few years later.

So, we were fortunate to have Paul as a mentor during our formative years. He certainly wasn’t the sweetest guy, but he was brilliant, and hopefully a very small part of his brilliance rubbed off on us.”

Peter J. Reilly