In volume elements in momentum space, for example in 3 dimensions, I’m familiar with notations such as d^3 k. And while I do see that in the text, I also see notations like dk^3. What is the difference in meaning of these two notations? ]]>

https://en.wikipedia.org/wiki/Sign_convention.

Apparently, particle physics (QFT) uses West Coast and the wikipedia relativity pages use the East Coast on. This also coincides with what Alex Flournoy mentioned in his excellent QFT class (https://inside.mines.edu/~aflourno/Particle/423.shtml).

By the way, I absolutely love your book, Jakob. I’m not a physics student but rather I am a computer science engineer who is also interested in QFT. I love your very logical presentation and the way you always explain things beforehand, rather than assuming that the reader is a 3rd year undergrad physics student. It would be great, however, to have more polished diagrams; I sometimes have trouble reading them. The way you notate the math transforms you are applying to each equation (one per line) makes it super easy to follow the mathemagic that is going on). But in 5.2.4 you made a leap up to the general solution of the Dirac equation that was very sparse and hard to follow. Perhaps it is outside the scope of a beginners book. But it left me wanting more.

I should mention that I first bought the Kindle book but I found that almost all the diagrams were pure black and most of the equations were misformatted So I had to return it and then I bought the printed version. I’m sure glad I did. This is the best book value that I have seen in the last 20 years!

]]>I enjoy reading your QM book; as usual, it is very well written!

Here is a quick question: In chapter 8, you say that P(reflection)=|A|^2 and P(transmission)=|B|^2. Later, when I plug E=U into your equations for the step potential (Section 8.1.1/2), I get A=1 and B=2. Something is not normalized properly… What are the correct probabilities for reflection & transmission in the case E=U? ]]>

The same question is for page 299 where for the formula |E2>=a+|E1> I’d rather expect sqrt(2)*|E2> = a+|E1>

I see some consistency here but fail to understand if it’s a problem or not. ]]>