Customer Reviews

Gauge Theories in Particle Physics, Third Edition - 2 volume set: Gauge Theories in Particle Physics: A Practical Introduction, Vol. 1 - From Relativistic Quantum Mechanics to QED

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The 3rd edition of that book clarified to a degree the fog left in my mind by a two-semester QFT course. The book is better suited for beginners than Peskin & Shroeder, Mandl & Show or Lahiri & Pal simply because it senses better the difficult points for beginners and tries to explain them at lower level. It focuses on the main concepts and doesn't try to `cover broad material in shortest time' or get into extreme computational technicalities totally irrelevant to beginners. The correct historical perspective of many ideas is given and the important historical papers are cited. The theory is frequently compared to the experimental results. Violin string is used as a prototype of a continuous system described by a classical field which is the first field quantized later. The book develops physical intuition showing how a scattering process can be analyzed in full QED (all fields are operators), in semiclassical approximation (all fields are operators except the EM field) or using the lowest level wavefunction approximation (all fields are treated like wave functions just like scattering in nonrelativistic QM) often getting the same result (see chapter 8). Important concepts like Feynman diagrams and Renormalization of a theory are first explored in a simple theoretical playground - a hypothetical `ABC theory' of three massive scalar fields with an interaction ABC term - and later discussed again in the case of QED with all the complications like fermions and Electromagnetic gauge field.

Topics discussed include gauge invariance principle; relativistic field equations describing free particles like Klein-Gordon and Dirac; Feynman interpretation of the negative energy solutions of Dirac eq. (no its not `antiparticle going back in time'); Dirac equation with EM field; Lagrangian and Hamiltonian densities for continuous systems; quantization of free fields like KG (real and complex scalar), Dirac and Electromagnetic field [the quantization is by postulating commutators/anticommutators, no path integrals]; Normal ordering of operators; Interaction picture for interacting fields, Time ordering of operators, Dyson expansion of the S matrix; Wick's theorem; scattering processes in QED at tree level; Ward identity; form factors for scattering from non point particle; parton model, Bjorken scaling; diagrams with loops, regularization and renormalization of ultraviolet divergences in QED.

It took me a month and a half to read the book and solve all problems (10 problems per chapter on average). The problems are exactly the ones every beginner should solve and usually revolve about filling in details from the text or proving statements in the text. Solving them is usually easy with a few exceptions and teaches you the typical computational tricks of the trade. You have to know quantum mechanics (at least have seen scattering theory) and special relativity. You have to at least have heard of Green function and contour integration in the complex plane. The book provides nice appendices about all these.

Not everything is crystal clear in that book, sometimes it took me a few days for an idea to sink in or I understood some paragraphs only after I read the whole book. Other ideas I did not understand at all. Sometimes it's hard to tell what they are trying to say although they say it several times from different angles ... The authors should work on expressing an idea in a direct succinct way once and for all instead of repeating several fuzzy versions of it. Overall that book made me understand MUCH more than a regular QFT course and I highly recommend it as a prep for such a course.

This book (2nd edition) has 15 chapters . I have just finished chapter 4 entitled QFT and I am compeled to write this review! After a year of studying of QFT informally I can report that this is the way to introduce yourself to the topic. I've been through Mandl & Shaw, Peskin & Schoeder, Ryder, Weinberg and a few others and this is heads and tails the BEST intro available. In 42 pages, Aitchison & Hey make the transistion from classical to QM and from QM to QFT as gracefully as I can conceive. For example, the transition from the discrete Lagrangian to the field Lagrangian is very explicit. One benfit of this is that the dependence of L on partial of phi wrt x is clearly motivated leading to the manifestly relativistically invariant form of L. They explicitly develop physical intuition at every step of the way - for example, this is the only book that I have found that explicitly asks the question where is QM's wavefunction in the QFT formalism? Answer - The vacuum to one-particle matrix elements of the field operators. The transistion from free fields to interacting fields is far clearer than any other treatment I've seen. I also appreciated that the problems were used to basically fill in details left out of the text. I was able to 'practice' the various kinds of manipulations that are required.