Is Quantum Field Theory for the Gifted Amateur Effective for Self-Study?

  • #1
Hill
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I'd like to hear your professional opinion on and experience with using Quantum Field Theory for the Gifted Amateur by Tom Lancaster and Stephen J. Blundell as a self-study textbook. Thank you.
 
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  • #2
It's pretty good, but the maths is still wild and woolly. I supplemented it by watching Tobias Osborne's lectures on YouTube. He had two courses on QFT.

The book has some nice insights.

The material is not dissimilar to David Tong's notes online.

https://www.damtp.cam.ac.uk/user/tong/qft.html

I also tried Zee's QFT in a Nutshell but he had lost me completely by page 5.

PS that's an amateur opinion, of course!
 
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  • #3
PeroK said:
PS that's an amateur opinion, of course!
A gifted amateur opinion, I would add. :smile:

I like "QFT for the he Gifted Amateur" very much. It's not so good for developing technical computational skills, but it's fantastic for developing conceptual understanding. (And I'm a professional, btw.)
 
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  • #4
I think concerning the conceptional point of view, emphasizing the importance of locality and microcausality and Poincare symmetry, Coleman's lectures are better:

S. Coleman, Lectures of Sidney Coleman on Quantum Field
Theory, World Scientific Publishing Co. Pte. Ltd., Hackensack
(2018), https://doi.org/10.1142/9371
 
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  • #5
PeroK said:
I also tried Zee's QFT in a Nutshell but he had lost me completely by page 5.
I tried several Zee's "in a nutshell" books. His writing style doesn't work for me. :frown:
 
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  • #6
PeroK said:
I supplemented it by watching Tobias Osborne's lectures on YouTube.
Unfortunately, I cannot learn "by ear" because of a form of APD.
 
  • #7
Usually the nutshells are too small for the addressed topics. There's no king's way to QFT!
 
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  • #8
Hill said:
Unfortunately, I cannot learn "by ear" because of a form of APD.
Hm, APD or not, you can't learn physics by just watching/attending lectures, but you have to do it yourself. Usually you start with attending a lecture or reading a book. That's just to get informed about the topic you want to learn, but then you have to practice by solving problems related to this topic for yourself. That's why it's good to have textbook with many problems (+solutions to check your work).
 
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  • #9
vanhees71 said:
you have to do it yourself
This is my intent.
vanhees71 said:
+solutions to check your work
Most / all textbooks don't provide these. I think the QFTftGA doesn't either.
 
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  • #10
Then the Homework section of this forum is a great opportunity!
 
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  • #11
vanhees71 said:
I think concerning the conceptional point of view, emphasizing the importance of locality and microcausality and Poincare symmetry, Coleman's lectures are better:

S. Coleman, Lectures of Sidney Coleman on Quantum Field
Theory, World Scientific Publishing Co. Pte. Ltd., Hackensack
(2018), https://doi.org/10.1142/9371
I should agree with vanhees71. Every time people ask for advice on what QFT textbook to use, Coleman Lectures always come up, and for a good reason. See them as some sort of "Feynman Lectures" on QFT. They are, perhaps, a bit more edited than Feynman's Red Books, but Coleman's students did a great job of keeping his spirit (and humor!). In my opinion, nothing can beat a verbatim lecture, edited or not edited. But the book is not for the light-hearted reader. Well, come to think of it, what QFT text is for light-hearted souls?
 
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  • #13
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  • #14
I like the book, although it had some confusing aspects to me. But its refreshing style makes it different from most other textbooks and worth the effort.
 
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  • #15
I like the book a lot so far in spite of the aspects mentioned earlier. One confusing aspect to me is typos in some derivations, although finding them can be viewed as built-in exercises in addition to the ones at the end of each section.

One such typo has been pointed to in this thread. Here is, I believe, another:

1701693564535.png


Three terms have missing factors ##e^{i\alpha}##, and the result should be rather ##D_{\mu}\psi \, e^{i\alpha}## to be non-trivial.
 
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  • #16
The first of law of physics books is the conservation of exercises for the reader. Either your exercise is to derive it yourself or rederive it because of typos.
 
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  • #17
Well, it's reassuring for textbook/manuscript authors if the readers take the typos with good humor ;-)). I wish I could deliver typo-free texts though...

One should, however, mention that it's the crucial point of "gauging" a global symmetry to a gauge invariance that the gauge-covariant derivative transforms as the field for spacetime-dependent phase factors, i.e., you introduce the gauge field ##A_{\mu}(x)## as a connection to define the gauge-covariant derivative, i.e.,
$$\mathrm{D}_{\mu}=\partial_{\mu} + \mathrm{i} q A_{\mu}.$$
It's defined such that for
$$\psi'(x)=\exp[-\mathrm{i} q \alpha(x)]$$
the covariant derivative also fulfills the same transformation law,
$$\mathrm{D}_{\mu}' \psi'(x)=\exp[-\mathrm{i} q \alpha(x)] \mathrm{D}_{\mi} \psi(x),$$
and the question is how ##A_{\mu}## transforms to ##A_{\mu}'##. Indeed
$$\mathrm{D}_{\mu}' \psi'(x)=(\partial_{\mu} + \mathrm{i} q A_{\mu}') [\exp(-\mathrm{i} q \alpha) \psi] = \exp(-\mathrm{i} q \alpha) [\partial_{\mu} +\mathrm{i} q (A_{\mu}'-\partial_{\mu} \alpha)] \psi$$
Since this should be
$$\exp[-\mathrm{i} q \alpha(x)] \mathrm{D}_{\mi} \psi(x) = \exp[-\mathrm{i} q \alpha(x)] (\partial_{\mu} +\mathrm{i} q A_{\mu}) \psi(x),$$
you get
$$A_{\mu}'-\partial_{\mu} \alpha=A_{\mu} \; \Rightarrow \; A_{\mu}'=A_{\mu} + \partial_{\mu} \alpha.$$
 
  • #18
vanhees71 said:
Well, it's reassuring for textbook/manuscript authors if the readers take the typos with good humor ;-)). I wish I could deliver typo-free texts though...

One should, however, mention that it's the crucial point of "gauging" a global symmetry to a gauge invariance that the gauge-covariant derivative transforms as the field for spacetime-dependent phase factors, i.e., you introduce the gauge field ##A_{\mu}(x)## as a connection to define the gauge-covariant derivative, i.e.,
$$\mathrm{D}_{\mu}=\partial_{\mu} + \mathrm{i} q A_{\mu}.$$
It's defined such that for
$$\psi'(x)=\exp[-\mathrm{i} q \alpha(x)]$$
the covariant derivative also fulfills the same transformation law,
$$\mathrm{D}_{\mu}' \psi'(x)=\exp[-\mathrm{i} q \alpha(x)] \mathrm{D}_{\mi} \psi(x),$$
and the question is how ##A_{\mu}## transforms to ##A_{\mu}'##. Indeed
$$\mathrm{D}_{\mu}' \psi'(x)=(\partial_{\mu} + \mathrm{i} q A_{\mu}') [\exp(-\mathrm{i} q \alpha) \psi] = \exp(-\mathrm{i} q \alpha) [\partial_{\mu} +\mathrm{i} q (A_{\mu}'-\partial_{\mu} \alpha)] \psi$$
Since this should be
$$\exp[-\mathrm{i} q \alpha(x)] \mathrm{D}_{\mi} \psi(x) = \exp[-\mathrm{i} q \alpha(x)] (\partial_{\mu} +\mathrm{i} q A_{\mu}) \psi(x),$$
you get
$$A_{\mu}'-\partial_{\mu} \alpha=A_{\mu} \; \Rightarrow \; A_{\mu}'=A_{\mu} + \partial_{\mu} \alpha.$$
This is explained in the book, too. However, they have the ##-q## factor moved from the field ##\psi## to ##A##:
1702056547116.png

The result, gauge invariance, is the same, of course.
 
  • #19
vanhees71 said:
Well, it's reassuring for textbook/manuscript authors if the readers take the typos with good humor ;-)). I wish I could deliver typo-free texts though... [...]
Macmillan Publishing Co., at least up to the '80s, was known to publish typo-free books. I own only two from Macmillan, Birkhoff & Mac Lane's "Modern Algebra", and Leithold's "College Algebra". Not only without typos, but beautiful editions, too!
 
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  • #20
Well, at this time they may have had still a true lectorate at the publishing companies. Today you are completely on your own with proof-reading...
 
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FAQ: Is Quantum Field Theory for the Gifted Amateur Effective for Self-Study?

What is the target audience for "Quantum Field Theory for the Gifted Amateur"?

The target audience for "Quantum Field Theory for the Gifted Amateur" is primarily advanced undergraduates, graduate students, and self-learners with a strong background in physics and mathematics. It is designed for individuals who have a solid understanding of quantum mechanics and special relativity and are looking to delve deeper into quantum field theory (QFT) without the need for a formal classroom setting.

What prerequisites are necessary for effectively using this book for self-study?

To effectively use "Quantum Field Theory for the Gifted Amateur" for self-study, you should have a strong grasp of undergraduate-level quantum mechanics, classical mechanics, electromagnetism, and special relativity. Additionally, familiarity with advanced calculus, linear algebra, and complex analysis will be highly beneficial. A background in statistical mechanics and group theory can also be helpful.

How does "Quantum Field Theory for the Gifted Amateur" compare to other introductory QFT textbooks?

"Quantum Field Theory for the Gifted Amateur" is known for its accessible and conversational writing style, which makes complex concepts more approachable. Compared to other introductory QFT textbooks, it provides a more intuitive and less formal approach, focusing on physical insights and conceptual understanding rather than rigorous mathematical formalism. This can make it more suitable for self-study, especially for those who prefer a less intimidating introduction to the subject.

Are there sufficient exercises and problems in the book to reinforce learning?

Yes, the book includes a variety of exercises and problems at the end of each chapter to help reinforce the material covered. These exercises range from straightforward calculations to more challenging problems that require deeper thinking and synthesis of concepts. Working through these problems is essential for gaining a solid understanding of QFT and for developing problem-solving skills in the subject.

Can "Quantum Field Theory for the Gifted Amateur" be used as a standalone resource for learning QFT?

While "Quantum Field Theory for the Gifted Amateur" is a comprehensive and well-structured introduction to QFT, it is often beneficial to supplement it with additional resources. These can include more advanced textbooks, lecture notes, online courses, and research papers. Engaging with a variety of materials can provide different perspectives and a more rounded understanding of QFT. However, for many self-learners, this book can serve as a solid foundation and primary guide through the basics of quantum field theory.

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