String theory crisis

[Anonymous No.12103683]

Normalfag here not a ton of science background. I keep hearing stuff from a bunch of different about how modern strong theory might be bullcrap. Is that true? Please help, am rarted.

[Anonymous No.12103729]

>>12103683
It’s still a ways away from connecting with our universe (it’s very good at constructing particle physics coupled to gravity but anything cosmological constant or cosmology related not so much) and the full theory isn’t known but it’s a huge success in terms of generalizing the frame work of QFT to include gravity (and there is some evidence that it is the only possible completion)
https://medium.com/@samuel.monnier/the-many-miracles-of-string-theory-5bd482c2f55b
This article explains it pretty well.

[Anonymous No.12103735]

>I keep hearing stuff from a bunch of different about how modern strong theory might be bullcrap. Is that true?
yes

[Anonymous No.12103758]

>>12103683
>>12103729
Also, my thoughts on popular anti-string books:
“Not Even Wrong” by P.Woit
I disagree with basically everything related to the central point but the historical aspects actually make it an alright read overall.
“Lost in Math” by Sabine Hossenfelder
Complete waste of fucking time, she’s so insufferable and retarded.
>>12103735
A lot of people/press have slightly warmed up to Hossenfelder’s/Woit’s viewpoint because it’s mainly technical reasons that makes string theory a worthwhile subject to study and it’s much easier to just believe string theorist are like French philosophers and jerking themselves off than learning the background material to really judge it for themselves.

[Anonymous No.12103795]

>>12103735
/thread
String theory is a proposed hypothesis with absolutely zero experimental evidence, and due to the nature of the hypothesis, it would be pretty much impossible to test it.

[Anonymous No.12103827]

>>12103795
Well it’s the only quantum mechanical theory that predicts a gravitational force and it predicts the strength is always weaker than the other forces. There’s already so many non-trivial consistency conditions satisfied by it that many experts believe that it’s the unique generalization to QFT that can include gravity (and it even sheds light on strongly coupled QFT behavior even when gravity is turned off). Applying simple criteria like what you’re saying is ignoring what it even is, and there’s nothing in science like it so you need to look more carefully.

[Anonymous No.12103840]

>>12103758
>than learning the background material to really judge it for themselves.
yeah, cuz im not dumb enough to throw my life and career away

[Anonymous No.12103857]

QFT is not close to a full theory idk why people like yo speculate shit about quantum gravity.

[Anonymous No.12103862]

>no testable hypothesis, not disprovable
string theory belongs on >>>/x/

[Anonymous No.12103872]

>>12103840
Then don’t be dumb enough to be swindled by Hossenfelder+followers and just say you don’t know. Or learn about the interesting steps that string theory has already taken. Or get good at QFT, then it’s a lot easier to see the motivation for string theory.
>>12103857
It’s not fully mathematically rigorous but it’s responsible for the most accurate predictions in all of science. Main issue is strong coupling. For lots of cases you can reduce string theory to tractable QFTs so that’s not a problem. Often you actually learn about QFTs from stringy intuition.

[Anonymous No.12103946]

>>12103872
>Then don’t be dumb enough to be swindled by Hossenfelder+followers and just say you don’t know
i could say literally the exact same thing to you about being swindled and baited by your intuition

[Anonymous No.12103997]

>>12103683
the other anon here did a good job defending string theory already. all i will add is that string theory, despite it being far from experimental testability, is by far and away the most successful attempt at a quantum theory of gravity that unites with particle physics. no “alternatives” even come close. and it led to a bunch of breakthroughs in pure mathematics just by virtue of people working out what it would mean if it actually did ally to the universe. its structure is extremely rigid and hangs together very delicately, despite what you might hear about the landscape. in fact the theory has 0 free parameters outside of things that are determined dynamically. in my opinion it is CLEARLY the theory of everything except for the fact that it implies a deeper theory of everything, M theory or F theory or some shifty type of holographic duality that doesn’t like M or F, and the real work of theoretical physicists is to find the right generalization.

however it is really fucking hard and even people who get PhDs in it don’t scratch the surface. Woit and Hossenfelder indeed don’t even have a PhD in the field of string theory, so they can fuck off. same thing with Smolin

Claud Lovelace’s last paper gives an interesting perspective on where strong theory will go. read that before becoming a Smolin retard

[Anonymous No.12104004]

>>12103946
Well yeah you can just say “no u” after everything in life but there’s actual meat to what I’m saying because there’s actual work that’s been done that backs it up. For a famous example, Seiberg and Witten conjectured how a certain gauge theory behaves at low energies when it’s coupling is extremely large (usual tools of Feynman are useless here) directly using intuition from string theory. They actually wrote the paper in a purely field theory way and argued that their answer was the only thing that could happen by consistency conditions. Any skilled field theorist at the time would see their solution as correct, but a rigorous calculation proving it actually happened about a decade later by Nekrasov.

The point is that the serious research that string theorists do today is not well expressed by any popular sources out there and there’s major communication gap with the public who often get tricked into thinking the only possible “meat” there can be to string theory is to measure quantum gravity effect that is uniquely predicted by it, completely ignoring what it actually even is.

Again, please read thIs to get a better idea: https://medium.com/@samuel.monnier/the-many-miracles-of-string-theory-5bd482c2f55b

[Anonymous No.12104028]

>>12104004
you can use logic and mathematics all you like, but experimentation is what defines physics

[Anonymous No.12104088]

>>12104028
I think you’re totally taking the interactions between theoretical understanding and experimental interpretation for granted with that statement and I’m pretty sure every experimental physicist I know would disagree. The thing I linked really explains why you’re thinking is inappropriate and too simple to understand the merit of string theory as a TOE candidate.
Lesson: it’s a pretty deep subject both physics and math-wise so you need to be open to not ONLY using what you learned from 8th grade on evaluating scientific theories.

[Anonymous No.12104316]

>>12104088
>a TOE candidate.
the universe doesnt have any feet, theres no reason for it to have a toe either

[Anonymous No.12104972]

>>12104316
>no toes and feet
How do you expect the universe runs?

[Anonymous No.12105011]

>>12103683
I'm an actual physicist and I'd add although string theory is certainly interesting in terms of being so gorgeous at times it's easy to be convinced that it must be right, string theorists are definitely on thin ice.
Far far too many string theorists engage in behaviour that would be totally unacceptable to any other physicist. They are far too often disconnected from any experimental discussions, and don't really care to make themselves accessible. This sort of behaviour is always concerning, and they make too many excuses for themselves.
They run a serious risk of getting lost in abstract nonsense, and many don't seem to care. I won't go so far as to say that string theory is not physics, but I would absolutely say that they generally don't behave in ways which are healthy for physics.
I say this as someone who was 100% behind supersymmetry until the LHC made me re-evaluate things, and I've since moved away from string theory.

[Anonymous No.12105014]

>>12104088
Anon what are your thoughts on the landscape. Im a layman who has been trying to follow this stuff. Ive read the general ideas of Tom Banks' string theory work. His takes on why the landscape doesnt work, and why holography might be the right direction to take this stuff is interesting.

[Anonymous No.12105016]

>>12105011
meant to say I'm an actual particle physicist, or at least was - I'm aware there must clearly be many physicists here already
One thing I strongly disliked was I would sometimes go to these talks by string theorists and they were completely incomprehensible to even other particle physicists who were big names too, as in I remember asking a guy who is almost a household name afterwards what he thought of this talk, and even he said it was incomprehensible, but the string theorists didn't seem to care, and particle physicists ought to be their closest allies.
I'd say the problem with string theory is almost more cultural than scientific. That's just my opinion though.

[Anonymous No.12105026]

>>12103683
It's hasn't made a single testable prediction in 60 years.

It's literally astrology.

[Anonymous No.12105060]

>>12103857
This
>>12103872
The mathematical caveats seriously makes the theory impossible to ground on a theoretical basis. If physics was just doing a bunch of techniques to reproduce experiments, there is no point in trying to force QFT into the theory it already has. It postulates the existence of of certain mathematical objects which then are interpreted. Approximate or numerical techniques only tell you things about the objects if you know they actually exist, if not then what the hell are you actually calculating? The problem comes from the fact that the interpretation comes from the full object not the approximation. That and the fact that it still cannot explain all the phenomena in the standard model. People are willing to throw it away just because the naive approach to QG is not renormalizable? Maybe a better theory at the level we are currently are should be a goal rather than dreaming with TOE.

[Anonymous No.12105108]

>>12105060
>mathematical caveats
would you mind elaborating?

[Anonymous No.12105169]

>>12105108
What is the hamiltonian (as an operator in a hilbert space) of the standard model? What is the hamiltonian just for something as fundamental as QED? These may be mathematical and abstract but the scattering amplitudes are calculated as they are because it is assumed they exist.

[Anonymous No.12105376]

>>12103857
Honestly this, trying to make QFT rigorous seems like a lot of fun, although magic shit like Padé approximants are super interesting as well.