QFT

[Anonymous No.6877040]

Is quantum field theory supposed to be a fucking clusterfuck of meaningless math that you can't grasp when you first learn it?

Seriously, the more I read about fucking generating functionals and Green's functions the less I actually understand

[Anonymous No.6877049]

There is an erroneous idea that you're not actually supposed to understand anything with the word "quantum" attached to it, so quantum theory is devolving into nonsense.

[Anonymous No.6877066]

>>6877049
>>6877040
You just lack the quantum understanding.

[Anonymous No.6877092]

>>6877040
Aren't Green's functions basic Electrodynamic?

Maybe take Calc and Linear Algebra first.

[Anonymous No.6877108]

>>6877092
no u

[Anonymous No.6877110]

>>6877108
I didn't want to offend you, it was an honest reply. You can't tackle higher educational physics without having a grasp on the maths behind it.

[Anonymous No.6877114]

>>6877049
>I can't understand it
>Therefore no one can understand it
>Therefore it has been invented to not be understood
Do not breed

[Anonymous No.6877131]

Don't worry OP, I have no fuckin idea what's going on either.

I wish they told us when we were in highschool that if you want to understand proper physics (Relativity, QFT, and all physical theories invented in the last 50 years including string theory) you need to take mathematics not physics.

[Anonymous No.6877133]

>>6877131
Where are you from? Your highschool must be doing a really bad job if the students get the impression that you can do physics without maths.

[Anonymous No.6877140]

Green's functions are just propagators bruh.
You do really need to get a class on complex analysis beforehand though.

[Anonymous No.6877159]

>>6877133

4th year theoretical physics student.

All the good phds and optional modules are mathematics or mathematical physics student only. I can't do them, and trust me I've tried, I almost failed.

[눈 ͜ಎ눈 No.6877162]

눈 ͜ಎ눈

[Anonymous No.6877172]

>>6877159
Well, then having studied maths wouldn't have helped you much, would it?

[Anonymous No.6877182]

>>6877172
It would if I majored in it which is what I explicitly just said both times.

Do try and keep up.

[Anonymous No.6877187]

>>6877182
You failled at the maths classes that were available to you and you think you could handle a real maths degree? Please.

[Anonymous No.6877198]

>>6877092
The bridge is literally Feynmans PhD thesis

http://en.wikipedia.org/wiki/Wheeler%E2%80%93Feynman_absorber_theory

>>6877040
My advise to learn it (and this is also the advice I give w.r.t phenomenological thermodynamics, where many people never become friends with concepts like enthalpy etc.) is to take a piece of paper and write down what the physical observables, in the end, actually are - what the theory is supposed to produce. Then take the spacetime concept as given and try to figure out the chain of mathematical concepts and expression from experimental input to theoretical output. That's not as easy or funny as it sounds - and you develope a positivist attiture.
If you simply try to learn what's in front of you, then you get confused where or why one does things. It's true that one has to spent far to long with passing from the definition of the path integral, through all the tricks, down to some Z[\phi] which seemingly mysteriously knows the answers to the poser questions..
An (even more) generic suggestion: Consult different resources. What do you work with?
If you're crying about renormalization and regularization in particular, do it on the grid or in statistical physics - that will clear up a big lot.

>>6877131
I'm pretty certain leaning GR is much simpler if you do it in the context of physics lectures. The math, you can literally imagine geometrically (maybe apart from the diffeomorphism group)

[Anonymous No.6877199]

>>6877187
When did I say I failed maths?

[Anonymous No.6877211]

>>6877198

I don't know if I'm autistic or something or that mathematicians don't understand what it's like to not be overtrained logically and mentally with mathematical background of everything they study

But I can't study something I don't know the maths to. I can't "wing it". Nothing makes any sense. It just becomes an exercise in rote memorisation and the entire field, particle physics for example, is reduced to sheer information that I have to remember.

It would have made so SO much more sense if I studied group theory and analysis properly before taking on particle physics, but that's not the physics way so instead it was taught as "the kaon is a particle with mass blah and blah blah fitting into the group SO(x)" and none of these words mean anything to me.

[Anonymous No.6877253]

>>6877211
Sure, if you do particle physics like chemistry, then it's no fun.
When you say you get lost in QFT.. and Green's functions.. I think about you're being confused about computations in the introductory materials... there I se \phi^4 n-point function shizzle. You want to do gauge field theory only after.
You "should" have some intuition for Lie groups in your 4th year, I guess. Group theory, representations where kaons or whatever might fall into, are thankfully a nice clear/algebraic topic to learn.