What's the joke /sci/?
oh haha, I get it. Don't you get it?
>>7938894
NO!!! I DON'T
>>7938879
There is none, it's a CERN cup.
>>7938879
Girl who thinks she knows physics when she should be working on her worthless art history degree.
>>7938879
there is no joke behind it. it's just the lagrangian for something. h.c. stands for hermitian conjugate.
looks standard model-
let me check
>>7939116
this desu
>>7938879
>glaring error
Embarrassing.
>first term
gauge field free lagragian (kinetic parts)
>second line
(massless) fermion kinetic parts + fermion-gluon interaction--I'm not sure why h.c. is included here, as this is the entire contribution.
>third line
mixing up the fermionic fields (the y_ij term) via an interaction with the scalar field (h.c. makes sense here since it seems only the fermion fields are mixed, not the anti fermions--also possibly phi is a complex scalar field)
>fourth line
kinetic term for the scalar field, not sure why the modulus sign. Even if it's a complex scalar field (D\phi)^2 is always understood to be the complex product. The last term are scalar field self interactions (including a possible mass term).
>>7939757
looking at it again, the scalar field interactions only depend on the field, not its modulus square, so it's a real scalar field. No idea why the modulus sign on the fourth line; the third line might be cleaned up with a gamma_5 term.
Standard Model Lagrangian. But it has an extra Hermitian adjoint that is being added which shouldn't be there because it's already in the term that it's being added to.
>What's the joke /sci/?
My associate's and transfer ambitions.
>>7938879
The joke is that it has an error on it, in the second line the +h.c term means + the hermitian conjugate, but it should not be there as the term already includes it.
>>7940037
I already said that.
>>7940038
>implying im going to read all the responses in a thread with double digit posts
>>7940056
>litteraly 18 posts
>>7939773
[math]\phi[/math] is a complex SU(2) doublet.
>>7940074
>18 is not double digits
wat
>>7940080
Hey, ive never understood. How do groups (or in the case of SU(2) and SU(3) and such its relevant that its a lie manifold) relate to particle physics?
Ive heard its based on the symmetries of the lagragian (like I think the EM field relates to U(1) because U(1) has a continuous symmetry under rotation and light is invariant under phase shift)
>>7941655
Gauge fields are like general relativity except with these groups used instead of rotations/boosts. If you take an electron and move it around a loop with a magnetic field through it, the wavefunction gets a phase change.
>>7941828
I stopped at special relativity.
>>7941655
Take a general Lie Algebra, [math] \left[ {{t_a},{t_b}} \right] = i{f_{ab}}^c{t_c} [/math].
Then the physical quantities involved in the theory, like the field strength, take values w/ respect to this algebra.
ex. [math] {F_{\mu \nu }} = {t_a}F_{\mu \nu }^a = {t_a}\left( {{\partial _\mu }A_\nu ^a - {\partial _\nu }A_\mu ^a + g{f^a}_{bc}A_\mu ^bA_\nu ^c} \right)[/math]
>>7941841
i learned something about lie algebras today thank you :)
>>7941841
I thought math was like... well, numbers and stuff
>>7941836
Well, you can see what happens when you move a vector around on a sphere (pic related).
Every point has its own tangent space. You can move a vector from one point's tangent space to another's, but if you move the vector around a loop, you don't end up back where you started.
It's the same concept with gauge fields, except instead of moving around vectors in the tangent space of the manifold, you're moving around abstract vectors that instead of rotations, transform under some representation of the Lie group.
In order to calculate stuff, it's useful to arbitrarily choose which vectors in the spaces at two different points we consider equal to each other. This is fixing a gauge. Once you've done that, the [math]\vec{A}[/math] field tells how the vectors change when you move them.
>>7941860
You push it even deeper too.
For instance look at the Lie Group, G, that corresponds to the Lie Algebra.
Construct the one-form, [math] A = {t_a}A_\mu ^ad{x^\mu } [/math].
You can then express the field strength as a two-form, [math]F = dA + A \wedge A[/math].
If you are familiar with Riemannian geometry, you can see this looks very similar to the curvature form, [math] R = d\omega + \omega \wedge \omega [/math], one a general Riemmanian Manifold.
So what we can realize from this is that our vector potential, A, can be interpreted as a connection on G-principal bundle. And following, the field strength represents a sort of curvature form for this principal bundle.
>>7941899
There's no joke. It's a cup they sell at CERN with the Lagrangian of the Standard Model written on it.
http://www.quantumdiaries.org/2011/06/26/cern-mug-summarizes-standard-model-but-is-off-by-a-factor-of-2/
>>7941899
dude, he just told you
>>7941918
kinda gay
![[caffeine] Koufuku Graffiti - 06 [720p][61491EFD].mkv_snapshot_22.03_[2015.12.27_22.21.17].png](https://i.imgur.com/MnDFb4d.jpg "[caffeine] Koufuku Graffiti - 06 [720p][61491EFD].mkv_snapshot_22.03_[2015.12.27_22.21.17].png")
>>7938879
The joke is that there are no gauge fixing terms. no FD ghosts, no counterterms and the currents aren't regularized.
Enjoy your divergent amplitudes you stupid whore.
>>7941928
The fuckin anime poster again
>>7941931
Why do you think physics has the principle of least action? We're literally the least funny people. At least the mathematicians can autistically laugh at their own unfunny jokes.
>>7941932
this
>>7941932
I really like this picture
the joke is there are people who are far enough into physics to know this and still are pretentious enough to put it on a mug incorrectly with zero context
the joke is that a female could never comprehend the meaning of the equations
>>7938894
>women
>STEM
There's your joke.
