Recent content by jakob1111

The book is amazing. If you get stuck somewhere, I recommend having a look at the http://michaelnielsen.org/blog/yang_mills.pdfn. His alternative formulations often help to understand things better.

Nothing specific. I would just like to see if there exist other reading notes that I haven't found so far. (Preferably on popular textbooks like Goldstein, Jackson, etc.)

Often when I read a chapter in a textbook and don't understand something, I find "reading notes" by other students extremely helpful. Oftentimes in these notes other readers have simply written down summaries of the sections in their own words. These descriptions of the "same thing" in...

@star apple regarding you original question: You can find a list of books in the same spirit as Woit's and Smolin's here, and essays written in a similar spirit here.

Fredrik, reading your comment about different "mindsets" I was immediately reminded of the following quote by Tony Zee: "Indeed, a Fields Medalist once told me that top mathematicians secretly think like physicists and after they work out the broad outline of a proof they then dress it up with...

All this disagreement and confusion about the status of "gauge symmetry" is really puzzling. So many smart people say things that are simply not true, at least not in general. In addition to the guys mentioned above, other prominent example would be Arkani-Hamed, who also likes to stress that...

Simply because I've never seen a similar story for the origin of non-abelian gauge symmetries :D If you know any reference where this is explained or have an idea how the story could go for non-abelian gauge symmetries, please let me know!

I think the story where abelian, i.e. U(1), gauge symmetry comes from is pretty straight-forward: We describe massless spin 1 particles, which have only two physical degrees of freedom, with a spin 1 field, which is represented by a four-vector. This four-vector has 4 entries and therefore too...

Thanks, however the author does not mention that there is actually symmetry breaking. The local symmetry is not and can not be broken. However, a global subgroup of it is actually broken I think, and in this sense there is symmetry breaking in the Higgs mechanism happening.

Sure, the connection between degrees of freedom and conservation laws is pretty straight-forward. However, as far as I know, the equations of motions, like the Dirac equation, the Klein-Gordon equation etc. do not follow from Noether's theorem. However, in some sense we can understand them as...

Breaking of a local symmetry is impossible. It is often said that therefore the role of the Higgs mechanism in the standard model is a different one. Namely, Once a gauge is fixed, however, to remove the redundant degrees of freedom, the remaining (discrete!) global symmetry may undergo...

A massless spin 1 particle has 2 degrees of freedom. However, we usually describe it using four-vectors, which have four components. Hence, somehow we must get rid of the superfluous degrees of freedom. This job is done by the Maxwell equations. To quote from Gilmore's "Lie Groups, Physics, and...

There are several reasons given in the literature, why UV infinities arise in QFT in the first place. My problem is putting them together, i.e. understand how they are related to each other. So... UV divergences arise and thus we need to renormalize, because: We have infinite number of...

This is fascinating, although it sounds a bit hard to believe. There are thousands of people who for for decades on topics related to supersymmetry, but still the fundamentals are still relatively unknown? I think one problem is that representation theory works for groups and Lie algebra, but...

Usually, one defines large gauge transformations as those elements of ##SU(2)## that can't be smoothly transformed to the identity transformation. The group ##SU(2)## is simply connected and thus I'm wondering why there are transformations that are not connected to the identity. (Another way to...