Recent content by Arcturus7

Thank you for the reply Chris. Everything you say definitely has merit. As far as liking HEP because I (was) good at it, I see where you’re coming from. My 4th year modules were somewhat mixed, I aced SM and Particle but had a bit of a mare in QFT, so it was a mixed bag for me. I did enjoy all...

Hey folks. I could really use some advice as I'm in a bit of a situation... I graduated in 2018 with a 1st in Theoretical Physics from a well respected UK uni, and at the time I was fairly sure that I wanted to pursue a PhD in HEP. I had tailored my final year MSci modules to reflect this, and...

Homework Statement Show that, after considering all 1 particle irreducible diagrams, the bare scalar propagator becomes: $$D_F (p)=\frac{i}{p^2-m^2-\Sigma (p^2)}$$ And that the residue of the pole is shifted to a new value, and beomes...

Hi - yes sorry, reading that post back it's very much word salad. Firstly, thank you for the links - I'll be sure to give them a read. Let me be more concrete with my question. I followed the hint as suggested in the question, and in so doing ended up with: $$U\approx 1+\epsilon X$$ And so...

I'm having a bit of an issue wrapping my head around the adjoint representation in group theory. I thought I understood the principle but I've got a practice problem which I can't even really begin to attempt. The question is this: My understanding of this question is that, given a...

Homework Statement Derive, using the canonical commutation relation of the position space representation of the fields φ(x) and π(y), the corresponding commutation relation in momentum space.Homework Equations [φ(x), π(y)] = iδ3(x-y) My Fourier transforms are defined by: $$ φ^*(\vec p)=\int...

Oh wow - okay thanks! I’m very surprised to see that we’re so far away. I would have expected both to be fairly similar, or even for GR to be further ahead purely because of the difficulty of observing weak gravitational signals. Very interesting stuff.

@PeterDonis I suspected the answer wouldn’t be cut and dried - things never are. Thanks for your helpful answer though! I was having the same trouble trying to work out a way to put them on an even keel. I basically was trying to find out some sort of quantitative way to compare our...

When we talk about energy scales, we often hear that we need new theories of gravity and particle physics when we hit the barrier that is the Planck scale. In particle physics we've only probed up to about 13TeV, which is way WAY below that level. It's easy for us to designate the energy to...

AH yes of course you're correct zwierz, I don't know what I was thinking when I typed that! Your comment is actually very helpful, thanks for the input!

I also liked this analogy but I'm not sure how much it helped me. In the case of circling a given latitude, if the tank barrel begins pointing towards north, then halfway round the Earth, where is the barrel pointing? Either; the barrel is pointing in "the same direction" as it was before, which...

Thanks for the responses. I saw that video and thought it made sense - the guy just sort of "slides" the tangent plane (and this the tangent vectors) along the surface of the sphere. I totally get why that loop leads to two vectors that aren't parallel. However I also watched a video of Leonard...

I'm currently in a GR class and have come across the notion of parallel transport, and I've searched and searched the last few days to try and understand it but I just can't seem to wrap my head around it, so I'm hoping someone here can clarify for me. The way I picture parallel transport is...

Ah I see - that's great! Thanks for clearing that up :)

I am confused about the production of bosons in annihilation processes. If we have a positron and an electron coming together and annihilating, we can always find a frame in which the net momentum is zero, which would suggest that a single photon can never be produced in such an interaction...