@Semiclassical I love the professor but he told me this stuff is "geometric"

for a certain definition of geometric, lol

algebraists have a very different idea of what that word means compared to geometers

indeed

@Semiclassical Otoh this stuff is strongly linked to the classification of constant curvature manifolds

and that is probably geometric

So

Why are gauge fields in field theory of the form $A_\mu^\alpha$

While the spin connection is $\omega^\mu_{ab}$

Aren't they both principal bundle connections

Or is it that Thing and you could write the spin connection with a single index but it's usually done with two due to the weird form of $SO$ stuff

@Slereah It's just notation - you could just as well replace the antisymmetric ${ab}$ on the spin connection by a single index $a$ - it's the difference of labeling $\omega$ by it's matrix components or by its coefficients in terms of the generators of the Lie group

it's convenient to write so(n) dudes with two indices

Ah yes

I vaguely recalled such a thing

So you could just use a single index ranging over... 10 indexes?

I forget the dimension of $SO(1,3)$

non physics physics question

we never have physics questions in here

I'm in my first year, and I find that if I don't revisit a lot of the stuff I learn in my own time, I end up forgetting it. How the hell do people manage to remember such a vast amount of information

Is it just the fact that you use it nearly every day?

@0celo7 except when I ask them

@Slereah It's 6 - three boosts, three rotations

which is a bit funny since i usually spend my time in the math chat :P

@Semiclassical lately you've been here

@ACuriousMind Ah yes, I was confusing it with Poincaré

yeah, i have

@Phase For me (and most people I know), yes. For @ACuriousMind -- he's not human.

maybe acuriousmind is just acuriousmindinajar

hooked up to a computer that enables him access to SE

what?

Brain in a jar

oh

In Alex Jones' basement

If we replace the double index by the single index, is the Riemann tensor only three indexes long

Oh wait, isn't there already a curvature form for the spin connection

@Slereah Yes

I forget what it looks like

if ACM were Alex Jones I wouldn't be surprised. Alex Jones is one of the greatest minds of the generation after all

@0celo7 sign of an effective troll: you know they're trolling you, and yet you're still annoyed

so, well-played

@0celo7 ACM is the one brain capable of playing 4 dimensional chess with Trump

@Slereah Yes. The difference between the spin and the standard Levi-Civita connection is that the spin connection is so-valued and the Christoffels gl-valued.

"geometric"

In both cases, however, the curvature is defined as it is for all gauge fields

@0celo7 I do wonder where your prof would locate the geometry in the subject

@Phase I'm a string theorist, of course I play 10-dimensional chess.

@Semiclassical the groups are symmetry groups of stuff

I think that's like when PDE people say their inequalities constitute applied math because the equations are used by engineers

it's not genuine

@Semiclassical Good that you recognize that. Ted thinks I'm a nazi.

well, if you pretend to be something, you're taking the risk that people will take you at your word :P

I never pretended to be a nazi.

Alex Jones is not a nazi

@ACuriousMind is German so he has to learn the German song

i'm not sure what i'd call Alex Jones beyond "crazy as balls"

@Semiclassical he's an entertainer

@0celo7 though when you see stuff like this you gotta wonder

again, when you pretend to be someone, you're accepting the risk that people will take you at your word

I think he has moments of subtle trolling.

@Semiclassical Joe Rogan is good friends with him and has confirmed that a lot of it is acting

I think most of the audience is ironic

ehhhh

I find it a lot easier to believe that Alex Jones is acting than his audience being ironic.

String theory must be unfortunate to study

It's both.

@Phase Say what?

My main reason being that Alex Jones doesn't just entertain on the show, he markets products

I can't think of anything less understood by the general population, and more loved as a "hey im gonna turn this into nonsense woo bullshit" tool by hippies and pseudo-intellectual people

Talking to a string theorist is the worst

I always try to pull out the truth from @ACuriousMind

But then again I spend my time in a flat earth / hippy group looking for things to be angry at so

@Phase Quantum mechanics.

and he always says "No that's not how it works!"

@Semiclassical more than string theory?

@Semiclassical Yeah I do have to wonder who buys that stuff. I love Alex but I would never buy any of that.

I feel like string theory, as its even more obscure, can be used with even more safety from criticism by random nonsensical people

In that quantum mechanics gets linked with consciousness stuff

Dude ST does too. You just have to go deeper

it basically reads like this:

Stranger Things had some awful science

"Everything is a vibration and string theory is about vibrations therefore consciousness is an energy vibration in our spiritual field" or shit like that

Stranger Things is also a science fiction movie

Something something compactification wormholes

hngg

Not even hard science fiction

It's basically a modern day ET

you should not expect much

Also spoiler

There are 0 movies that are hard science fiction

@Semiclassical his supplements have lead apparently youtube.com/watch?v=qTB8Hl_dp8M

@ACuriousMind can I have my PhD in String Theory yet for my "Consciousness vibrational harmonics in physical spiritual (infinite + 3)D space" yet

I still would say quantum, though. The problem is that you can easily find stuff written by Wigner and von Neumann that makes it sound like consciousness is essential to QM

Oh yeah. And Schrodinger

Didn't he argue that consciousness is a requirement?

and you had a solid contingent of physicists in the 70s who bought into that for at least a period

Also Penrose RIGHT NOW

@Phase Nothing in that sentence requires "string theory", you can peddle the same kind of nonsense with a misunderstanding of ordinary quantum field theory :P

that old coot

breaking the "shut up and calculate" law should be punishable by death

riiight

I'm more fond of "shut up while you calculate"

Well investigating QM interpretation is useful

or at least

you know

a slap on the wrist

But fraught with peril

is this good enough?

By contrast, I don't think the actual scientists involved in string theory have had any truck with the 'spiritual vibrations in teh universe' crap

So @ACuriousMind

How do you compute an actual process in string theory

I'd love it if there was a historical research effort to find the first person who pioneered the subject and it turned out to be a crystal healing instructor peddling chakra therapy

So quantum mechanics, for better or worse, has a harder time inoculating itself against quantum mysticism bullshit

Like particle scattering

"Yeah man just model your spirit as a brane man"

To the extent that people abuse string theory, I'd think it's just extending the quantum mysticism crap into another dimension

Honestly quantum mechanics is needed in this chat room

for instance

The vacuum fluctuations that lead to boltzmann brains that go on Stackexchange, get 100 rep, join the h bar and star all of @0celo7 's bad statements to drag admins here

@Semiclassical quantum mysticism + more dimensions

@0celo7 pretty much

I have zero bad statements and please do not say such things

it's offensive to me and my children

oh, you also have the notion of zero point energy in QM

@Slereah Sum over worldsheets: In the same way that a scattering process in ordinary QFT is a sum over Feynman diagrams, a scattering process in string theory is a sum over 2d "string diagrams", i.e. Riemann surfaces. The expression for this perturbative string S-matrix is well-known and its agreement at low orders/energies with the scattering functions of 10d SUGRAs are essential to the claim that the five string theories correspond to the five possible 10d SUGRAs.

and boy howdy that's an inspiration for crackpottery

Didn't you tell me a few weeks ago that this wasn't how you did it?

What other lies have you told me!

finally, quantum nonlocality

which people somehow translate into "you can change things at a distance with your mind, maaaan"

nonlocal correlations do not imply nonlocal signalling gtfo

you can

Just will yourself into a state of dementia

all of sudden everything around you is changing

I admittedly do find quantum nonlocality pretty hard to understand

mostly how that can be compatible with Lorentz-covariant QFT

ew this is awful. I think I have to write out the cosets explicitly

it evidently is

@Slereah I think what we last discussed about this was that the string S-matrix is not a QFT S-matrix, i.e. string theory is fundamentally different from QFT in that this S-matrix expression is postulated, not derived, and contains essentially a sum over all the CFTs on the worldsheets

@ACuriousMind is faking my death possible?

but that doesn't mean I understand how

I find everything hard to understand until I have a grasp of the maths and unfortunately I haven't learnt enough for any of that yet

@ACuriousMind No, I got that

I think I asked you about like... States?

Like boundary conditions

@0celo7 Apparently you just need to let your driver's license expire, no? :P

@ACuriousMind my renewed one is good for 8 years

lool

@0celo7 depends, who to? You can't hide from ACM because he can just slip into one of the 6 other dimensions to sneak up on you

ACM needs to hide from me, not the other way around

Also I think I asked you about like

@ACuriousMind OH NO

Does a single string actually represent a state?

HOW DO I KNOW THESE REPS ARE SIMPLE

Since a single worldline in QFT does not actually represent a real state

is it the same for string theory

Are real states actually a sum of infinitely many strings

@Semiclassical how many quantum states do I need to decalcify my pineal gland and open my third eye

@Slereah The analogy is pretty good there - the string doesn't represent "a state" either. The states live in the quantized theory of the Polyakov action of the free string, they don't correspond to anything particular the string "does" or "is".

I think I have to compute $\langle\chi,\chi\rangle$ and it gives the number of splittings?

ugh

Does anyone know a good reference re: Bell's theorem vis-a-vis QFT?

I couldn't even get an answer as to what an observer is in QFT on PSE

Moretti didn't know?

He didn't answer, at least

Main things I've seen on PSE in this regard are Lubos rants

and uh

he must have not seen

he would know

@Semiclassical Lubos needs to be on Infowars

pretty much

@ValterMoretti Saint Moretti please help

@Semiclassical What sort of reference are you looking for? Does anything in Bell's theorem depend on any particulars of the quantum theory that would break in QFT?

@0celo7 can you stop please? It's like you're implying that InfoWars is an inaccurate or biased news source

hmm

Weinberg's QM book has something short but interesting on Bell at the end of his book

it's not that I'm looking for, no

@Phase Am I? Lubos Motl is the Einstein of our generation.

That is, I think Bell's theorem is a sufficiently general statement about quantum theories that I don't see how there would need to be special consideration of it in the context of QFT

Einstein was persecuted for being Jewish, Lubos for...stuff.

Being an ass (donkey), and stuff.

It's ableism

I'm more wondering how nonlocal correlations are described in QFT? That doesn't sound quite right, though.

...

The timeline doesn't make sense...

so we've got lubos motl inventing time travel to look forward to.

neat.

@Slereah Don't call people insane, please.

I'm 90% sure that you can just consider disjoin regions of the field as observers in QFT but I don't have a clue

@Semiclassical *backward to

lmao

get b&

@0celo7 the prophet

@Semiclassical I'm not sure I understand what you mean by that question.

Slereah if you're still among us give us a sign

I am ded

RIP

Noooo

One of my censored message was a classic Simpsons reference, btw

btw if you hold a meeting to talk to a dead physicist is it called a Scieance.

@ACuriousMind Suppose we get a doctor's note saying someone is insane. May we then reference the fact that they are insane?

@0celo7 No doctor will use the term "insane". If someone has a known medical condition you may of course refer to it.

So

If I said ____ has autism

Is that fine?

rightdiagnosis.com/i/insanity/intro.htm

@ACuriousMind internet medicine disagrees

I think we're being sorta silly here. Whether or no he's crazy is beside the point

Ok how about this

Is it ok to say a user acts insane, since it's less of an insult to their person and more just describing what they do / say

@Semiclassical that's offensive

@0celo7 Your own reference contradicts you, it says in the very first sentence the term is non-medical :P

@ACuriousMind that's what I get for not reading

I'm sure some of the soviet doctors in Lubos' homeland would use the word

@Semiclassical That's also not fine to say, no matter how true you think it is.

rekt

ehh.

i withdrew it, but

holding standards of 'offensiveness' for LM seems rather silly when he seems to revel in being offensive

I object to the 'insanity' aspect because of how mental health gets used as a pejorative.

@Phase The question is why you would say that. If you're using it -explicitly or implicity - in a degoratory manner, it is not fine. If it has relevance to the conversation and is not used in a degoratory fashion, it would be fine. Once again it is not words, but intent, that matters.

@Semiclassical The Be Nice policy extends even to those who do not abide by it outside of SE.

I'm beginning to get unreasonably angr

*angry

Meh.

I've been led to believe that constant proper acceleration is fine, and that it corresponds to a hyperbola path

from sources I've read