Wednesday, October 06, 2010


That is, Mystified in Italian.

Today was sunny and as my hearing and consequently my energy is slowly returning Clare and myself took a walk up to the top of the Mendips. Yesterday evening was Clare's first class in Italian (at Strode College in Street) and all the way up the hill I was accompanied by a monologue. First we had the numbers up to 20 in Italian. Then she asked herself her name in Italian and then spelled out the letters in an Italian pronounciation. Then we had a recital of our telephone number. Finally she asked me "Come stai?" - this means "How are you?"

As it was wet underfoot I had decided to wear some extraordinarily expensive Gore-tex shoes I had foolishly bought from a shop called Ecco at the beginning of the year. They have never fitted properly and I was experiencing frictional pain in both my heels. I guess it makes a diversion from the clog in the ears. At the farm I could bear it no longer and took off each shoe in turn as Clare applied plasters: I now have blisters.

So the answer would have been "Non è fantastico" had I any Italian.


Why is Quantum Field Theory so hard (as all agree it is)? I think it's because there's a step function from undergraduate maths and physics to get to grips with it. In particular you need a good, solid (not just an introductory) understanding of non-relativistic Quantum Mechanics. You need familiarity with the Lagrangian formulation of dynamics. You need to be really comfortable with the mathematics of special relativity including tensors and the Einstein summation notation; and Lie groups. Oh, and the Calculus of Variations which is used ubiquitously.

Once you have internalised all that, you can get started.

Naturally I was interested in the best textbook as a companion for this journey.'s webpage for "Quantum Field Theory" gives plenty of choices, starting like this.

1. Quantum Field Theory by Mark Allen Srednicki (Hardcover - Feb 5, 2007) Buy new: $75.00.

3. Quantum Field Theory in a Nutshell: Second Edition by A. Zee (Hardcover - Feb 21, 2010) Buy new: $65.00.

4. An Introduction To Quantum Field Theory (Frontiers in Physics) by Michael E. Peskin and Dan V. Schroeder (Hardcover - Oct 2, 1995) Buy new: $80.00.

5. Quantum Field Theory by Claude Itzykson and Jean-Bernard Zuber (Paperback - Feb 24, 2006) Buy new: $39.95 .

6. The Quantum Theory of Fields, Volume 1: Foundations by Steven Weinberg (Paperback - May 9, 2005) Buy new: $59.00.

7. Quantum Field Theory Demystified by David McMahon (Paperback - Feb 29, 2008) Buy new: $24.95.

8. Quantum Field Theory by Franz Mandl and Graham Shaw (Paperback - May 25, 2010) Buy new: $55.00.

9. Quantum Field Theory by Lewis H. Ryder (Paperback - Jun 13, 1996) Buy new: $85.00.

10. Quantum Field Theory (Mathematical Surveys and Monographs) by G. B. Folland (Hardcover - Aug 26, 2008) Buy new: $89.00.

11. A Modern Introduction to Quantum Field Theory (Oxford Master Series in Statistical, Computational, and Theoretical Physics) by Michele Maggiore (Paperback - Feb 10, 2005) Buy new: $70.00.

12. Quantum Field Theory: From Operators to Path Integrals (Physics Textbook) by Kerson Huang (Paperback - May 11, 2010) Buy new: $130.00.

I spent quite a while reading the reviews, which were often contradictory. Some of the titles are apparently too computational while others are too advanced. Some are too uneven, others too unintuitive. In the end the book which seemed to best match my needs: beginner, need for conceptual clarity, modern mathematical treatment was none of the above. I ordered:

"Gauge Theories in Particle Physics: vol. 1: From Relativistic Quantum Mechanics to QED (Graduate Student Series in Physics)" by I.J.R. Aitchison and A.J.G. Hey.

That can sit on the shelf as a reference while I work through "Introduction to Elementary Particles" by David Griffiths. This is more of an experimentalist's account but by that very fact it's an accessible tour around the subject.

"Quantum Field Theory Demystified" by David McMahon, which I was working through is more mathematical but its very brevity means that the maths is highly unmotivated. Result follows result but the trees dominate the wood.

The various reviewers of the many books above are united in that QFT can't be acquired from one book alone and shortly I'll have four, counting Zee's "Quantum Field Theory in a Nutshell". I wonder how much time I'll have to progress this?