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3:10 AM
@Semiclassical these might be fun/handy for remote physics teaching/learning falstad.com/mathphysics.html
there's also some links to more of the same kind of stuff on other sites
 
3:21 AM
though seeing is believing, and i like your idea of physically building them at home
 
4:01 AM
Does anyone have a good explanation for why the existence of a possible gauge anomaly is characterised by the fifth homotopy group of the gauge group being non-trivial
I know that such groups have to have a complex rep for the fermions to live in, are they related?
 
4:42 AM
@antimony i'm fond falstad's circuit simulator
 
5:35 AM
nice :)
 
5:59 AM
@ACuriousMind with strong nuclear force i guess you can at least make the argument that, without it, nukes wouldn't be possible (though we hardly understood it when we made them). but what grand human transformation would you ascribe to the weak nuclear force?
 
6:09 AM
in Physics noob tries to get better (ft.John rennie), 4 mins ago, by John Rennie
Or I guess it's fairer to say that both QED and Maxwell's equations are derived from the same Lagrangian.
can anyone tell me what is this lagrangian?
 
In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction. In technical terms, QED can be described as a perturbation theory of the...
 
6:29 AM
@satan29 you only need the $-\frac14 F_{\mu\nu}F^{\mu\nu}$ part of the QED Lagrangian for Maxwell's equations
 
7:21 AM
@Semiclassical there are methods these days to detect reactors using neutrino detectors
 
7:31 AM
@Slereah do you mean mostly for compliance and intel, or also scientific insight into reactor processes? or both?
 
whatever you need it for!
 
cool
 
Never worry too much about applications, in my opinions
Twin primes were discovered in the 17th century and it wasn't until cryptography in the 60's that they became "useful"
 
thats the beauty of it imo :D
 
ehh
number theory would still be beautiful even if it never became useful
 
7:40 AM
and yet people would still bitch
 
between a universe where number theory is lovely but irrelevant, and a universe where the NSA has a material interest in what progress is made on the Riemann hypothesis
i'm not sure we got the better deal
 
Why ask about the standard model, then
Isn't it beautiful on its own
 
you're talking to a guy who did condensed matter theory. defending the beauty of the standard model is happily outside my jurisdiction
 
but apparently questioning its utility is!
 
lol
i don't think the standard model needs defending. It Just Works. (Except To The Extent That It Doesn't But We Don't Really Know About That.)
 
7:52 AM
Many things work but are of questionable utility
 
 
1 hour later…
fqq
9:20 AM
@Semiclassical nuclear power (and weapons) were made possible mostly by understanding the weak force, no?
 
 
1 hour later…
10:26 AM
If the process of constructing an "extended $\mathcal N$-supersymmetry algebra" involves giving the supercharge an additional index that runs to $\mathcal N$, does this mean that the spinor index on it is always two component?
So the supercharge for the $\mathcal N=4$ supersymmetry algebra for example is sort of a four-component vector with each component being a two component spinor
 
@fqq I'm pretty sure we had only the Fermi theory of $\beta$-decay when we built nuclear reactions - the modern understanding of the weak interaction as the result of the spontaneously broken electroweak theory hails from the 60s (Glashow model, Goldstone with spontaneous symmetry breaking, Glashow, Weinberg & Salam w/ electroweak theory).
The first proposal of W/Z bosons as force carriers seems to be from around 1949 according to this, so no, we really built nuclear bombs and reactors without really understanding what we were doing.
@Charlie don't think of it as "the supercharge" - you're just introducing $\mathcal{N}$ supercharges and numbering them
and yes, each supercharge is still a spinor
 
ok ty
 
 
6 hours later…
4:14 PM
Any good books, or articles explaining the Jamin interferometer?
 
 
1 hour later…
5:40 PM
@ACuriousMind I think for a while the weak interaction was a 4-fermion thing
With harsh points rather than propagators
That was the 60's idea I think
 
Yo, everyobe
Muon G-2 Results out today!!!
was waiting for it, tho, I admit I don't understand a single thing of it.
@JohnRennie @Slereah you understand that?
damn ugly! going to sleep at 3 and waking up at 5...
I'm on sleep medications
that sucks
life, covid and all
 
I don't touch experimental
It is a scary place
 
Me too....
beli scary
 
I prefer to stay in the platonic realm thank you
 
Belcom vro
Anyone here watching Match tonight?
lol
very interesting match actuallie
nop
 
5:49 PM
imagine having to keep track of $10^{80}$ particles and pretend most of them aren't influencing each other
 
Imagine having a slight problem in tracking system and the particles influencing each other.
 
@ACuriousMind What was moved? I wanted to see them
 
I could be looking at a star right now that's 30 parsecs away and if I post about it it would be an influence on local experiments
What if George tampers data according to astrology????
 
I've a cool idea
of an alternative formulation of theory of everything
@Slereah u there>
?
 
5:53 PM
No.
 
@Slereah that's the Fermi theory, no?
 
@ACuriousMind I think so?
 
Let's mix all pseudoscience, homeopathy, alchemy, astrology, NLP and everything and make a new theory of everything pseudoscience version, then we'll publish and sell our generalization
 
I don't remember much about it
 
hehehe d(^_^)b
 
5:55 PM
I think it was just $\psi^2 \eta^2$
just bumping spinors
 
$\psi^2 \eta^2$
cool theory
 
electron spinor and neutrino spinor
that sort of thing
 
okay, I understood everything
 
Good, because I don't remember a lot of places that talk about Fermi theory
 
okay sir, I understand
 
5:57 PM
Cool neutrino dudes might but I only remember it from that weird article about black holes radiating neutrinos
 
okay sir, I understand
@Slereah What is your IQ Score?
 
(turns out they do not radiate neutrinos even if Fermi theory is true)
@RewCie 1
 
@Slereah Damn! That's very sad... that made me emotional too.
 
It's in "Magic without magic", if you want the emotional rollercoaster
 
@Slereah Hey king, you forgot couple of zeros in the end
 
5:59 PM
a bunch of papers in honour of Wheeler, which is a weird theme for a physics book
 
Just In: India became the country with fastest vaccination rate today.
The rate after end of the month is projected to be 3x of the rate now
@ACuriousMind Google Suggests ACM Profile Pic
Google suggests Slereah Profile PIC
Damn! I was searching for Profile Pic for me and then suddenly, This came to me - > reddit.com/r/IndiaSpeaks/comments/lhkyvk/…
Goosebumps all over my body
My viral twitter thread which got me 700 followers in 24 hours has been viral in Reddit too
I guess, I should make a new reddit account then
check that too
I've multiple viral reddit threads on me
damn! I'm feeling myself as a celebrity
whatever, fsfsfsfsfsfsfs ignore
Twitter made me famous.
 
Calm down.
 
okay vro
no viral threads from now
 
fqq
6:36 PM
@ACuriousMind yes I agree. My point was that the Fermi theory is a first understanding of the weak interaction, not the strong one
 
7:00 PM
the early form of the strong interaction was the Yukawa theory, I think
Which is kind of valid in the simplest approximation?
If you assume everything mediated by spin 0 mesons
I don't know how much this is related to actual nuclear power, though
I'm not big on engineering history
 
7:26 PM
@Slereah I think Meitner and Frisch had correctly identified the fission process and estimated the energy simply using a classical model using charge and radius.
 
Like the liquid drop model?
idk
 
yes
And chain reactions were already known from chemistry.
Szilard had already thought about doing the same with neutrons before fission was discovered.
So next they had to confirm that there are really neutrons produced by fission.
experimentally determine the relevant cross-sections and discover a way to slow down neutrons
so then Chicago Pile number 1 would be the next big step
 
100 point bounty that may be of interest to people here!
5
Q: Example of a standard/archetypal/simple 4-band gapped condensed matter model with analytic results?

TribalChiefI am looking to study Berry phase-like phenomena in a gapped 4-band material model. In particular, I want to numerically and analytically calculate the Abelian Berry curvature integral of each band over some region of k-space. It should be easy to calculate the Chern number of this system. Howeve...

 

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