Bonus Material

No-Nonsense Quantum Field Theory

- A great discussion of general wave properties and dispersion can be found here. Moreover, a great book on classical waves is The Physics of Waves by Georgi.
- A more detailed discussion of symmetry breaking and the Higgs mechanism is available here and here.
- To learn more about the philosophical aspects of the renormalization group and related topics, a great starting point is Renormalization Group Methods by Williams.
- If you want to learn more about spinors, try Spinors for everyone by Coddens and An introduction to spinors by Steane.

Best regards, Jakob. Thank you for your clear and simple explanations. I have a question. On page 50 you imagine a clock attached to an object that moves arbitrarily. Doesn’t the acceleration that this clock undergoes alter its proper time register in any way?

Strictly speaking, this image is only valid for infinitesimal time intervals. During an infinitesimal time interval, the velocity is constant and hence there are no problems due to acceleration.

Jakob,

Congratulations for writing books for true beginners. Established authors might take exception to your comments about them wanting only to show off their knowledge, but I think you’re correct here.

I was wondering: when you find typos, do you correct them in subsequent book printings, or are you waiting for a future edition?

Thank you.

Thanks Felix!

I update my books regularly. So instead of collecting the typos and then doing a big update (Edition 2), I do many small updates (Version 1.1, Version 1.2) etc.

Best,

Jakob

1. I am kind of struggling with upper and lower indexes of vectors as it looks for me the notation is opposite to what I could see everywhere. That is, normally vectors are using upper indexes and co-vectors are using lower indexes, so when lower indexes are used, the space coordinates are taken with negative sign, but in this book it is quite opposite. Just wondering why?

2. In (3.11) formula, did not we need to take a complex conjugation when writing the left vector? Then the result would be +1, not -1

1. This is just a convention. We also have the freedom to choose between the “West coast metric” (+,−,−,−) and the “East coast metric” (−,+,+,+).

2. The normalization condition in Eq. 3.9 is without complex conjugation. The Minkowski product of two four-vectors only involves transposition and the Minkowksi metric.

Hope this helps and let me know if you have any further questions!

Hello Jakob, thank you for writing such a fantastic textbook. I wish I had all of your no-nonsense series available during my undergrad years. I have one comment, on p.87 you mention parity transformation as transformation which mirror coordinate axes. Obviously, mathematically you mean (x,y,z) –> (-x,-y,-z). To the reader, this might create some confusion, specially with regards to the word mirror and the figure on p.87. Usually when we say mirror (or mirror reflection/transformation), we tend to picture a reflection about the x-z plane, thus mathematically (x,y,z) –> (x,-y,z). Also, it would be helpful if you could add a… Read more »

Thanks Fahim! I will add a comment in the next edition of the book.

Hi Jakob

I just began reading your book.

Could you possibly clarify a confusion for me.

You wrote on page 24, “an elementary excitation of the electron field is what we call the electron.”.

What bothers me is this: Say, an electron in orbit around an atom gets excited. This means the excited electron was part of the electron field.

Is this electron field local to that atom or non-local to all possible existing electrons everywhere?

Hi,

there is just one electron field and all electrons are understood as excitations of this electron field.