Is String Theory the Ultimate Meme?

[Anonymous No.9982179]

Real answers please.

[The Lord No.9982196]

The ultimate meme is to think you get on my bad side and have descendants be alive in the future.

[Anonymous No.9982205]

>>9982196
I want to learn physics from the master himself. Please teach me!

[Anonymous No.9982206]

>>9982196
wut?

[Anonymous No.9982210]

>>9982196
i googled and got some RA in georgia?

[Anonymous No.9982245]

>>9982210
You should have Binged him.

[The Lord No.9982251]

>>9982205
The key, IMO, to learning physics is to sign up for college and not skip your physics classes, and also do all your homework. Barring that, my book hits on most of the big picture issues that will make you sound smart enough about phsyics to other people who didn't matriculate through a physics curriculum

The General Relevance of the Modified Cosmological Model
http://www.vixra.org/abs/1712.0598

[The Lord No.9982255]

>>9982210
>georgia?
Nevada more likely, or Syria or Iraq. Or maybe some barge in the ocean. Could be Georgia though, but not my first guess.

[Anonymous No.9982439]

This has gotten me all tied up.

[Anonymous No.9983294]

>>9982179
i like string theory threads

here's my take on whether or not string theory is the ultimate meme

string theory initially started out pretty well -- some guys were working on modeling hadrons with strings, but they realized that they could pop out a spin 2 particle in their equations. so they said "hey fuck maybe a quantum theory of gravity". that's cool.

then it turned out that string theory requires supersymmetry. and okay, fine, they thought string theory was a really natural way to get the gauge couplings to unify and simplify the model in a beautiful way, provided that they found susy particles with a mass at or near 1 TeV. so far so good. so far, so good, but still, they couldn't turn string theory into a real theory -- they still couldn't calculate anything. fine, they thought, in a few years

then it turned out that string theory needed to have 10 or 11 (currently 11) dimensions, that's annoying. but okay, the other 7 can be compactified so that they're too small to be observable, fine. but they need to compactify in a particular way so as to give us something that looks like the standard model

this is where it got hairy. it turns out there were 10^500 different ways to compactify string theory, and each gives completely different theories. uh oh.

but no worries, cosmologists have wacky ideas like chaotic inflation! so therefore we might just get lucky and happen to live in a universe where we got lucky to one part in 10^500! yay for cosmology wacko theories!

then it got worse. the tevatron didn't see SUSY. and neither did the LHC, even at higher energies.... but hang on, SUSY can still survive! it just doesn't show up where it naturally would, instead, you can fine tune it in super arbitrary ways so that it stays hidden and unobservable! oh but wait, didn't we design susy to solve the problem of the SM looking like it had super arbitrary stuff? hmmm

(cont'd)

[Anonymous No.9983299]

>>9983294
(cont'd)

so, SUSY wasn't found where it had to be to solve the problem it was designed to solve. throw it away? "REEEE" shout the string theorists. "we need our SUSY! even though it introduces the same problem it tried to solve, we need it because our stuff relies on it! and our stuff pops out a graviton!"

meanwhile they still have the problem of their theory not having a unique solution, and relies on luck to 1 part in 10^500 ("but hey, muh chaotic inflation!!!"), and they aren't even CLOSE to having any observational evidence because they STILL haven't worked the theory out to the point where they can calculate a single goddamned thing. 50 years it's taken them so far.

and guess what they say? another 50 years before they can calculate a single goddamned thing.

and meanwhile Vafa has shown that string theory is probably inconsistent with a positive cosmological constant and (vanilla) inflation

verdict: MEME

[Anonymous No.9983307]

>>9983294
oops i made a typo here
>and okay, fine, they thought
>*SUSY*
>was a really natural way to get the gauge couplings to unify and simplify the model in a beautiful way, provided that they found susy particles with a mass at or near 1 TeV.

[Anonymous No.9983314]

>>9983307
Good explanation.

[Anonymous No.9983651]

>>9983294
>>9983299
Came to offer similar criticism but anon did a more thorough job than I would care to do. /thread

[Anonymous No.9984148]

>>9983294
>then it turned out that string theory needed to have 10 or 11 (currently 11) dimensions, that's annoying. but okay, the other 7 can be compactified so that they're too small to be observable, fine. but they need to compactify in a particular way so as to give us something that looks like the standard model
Wrong. The IIA theory develops an 11th dimension at large coupling, but IIB doesn't. Because IIA and IIB are T-dual, you can't say string theory predicts 10 or 11 dimensions, it can be either depending on how you choose to describe your theory: ST changes how we view spacetime so radically that the number of (compact) dimensions isn't fundamental!
>so far, so good, but still, they couldn't turn string theory into a real theory -- they still couldn't calculate anything. fine, they thought, in a few years
String theory makes plenty of predictions, they're just at such high energies that we can't test them right now. Also, having SUSY breaking at 1 TeV helps with the some aspects of particle physics, like the hierarchy problem, but string theory doesn't require this at all. Indeed, it makes perfect sense for SUSY to be broken at the only natural scale in ST, the string scale (near the Planck scale).
>it turns out there were 10^500 different ways to compactify string theory, and each gives completely different theories. uh oh.
It might be possible to rule loads of these out, or show them to be non-perturbatively equivalent (conifold transitions, for example). There might be one particular topology that counts for most of the low energy models. If we found such a thing, we could safely assume we are compactified on that topology, and then focus on studying the different fluxes on that manifold. At least it's a finite number, unlike the possible different quantum field theories!

[Anonymous No.9984168]

>>9984148
>>9983299
>and they aren't even CLOSE to having any observational evidence because they STILL haven't worked the theory out to the point where they can calculate a single goddamned thing. 50 years it's taken them so far.
You have clearly never actually studied string theory, just read about it online. Go pick up BBS or Polchinski and get to work.
>and meanwhile Vafa has shown that string theory is probably inconsistent with a positive cosmological constant and (vanilla) inflation
There are dS models of ST, and lots of theorists disagree with Vafa's claims, but even if he's right that doesn't change anything: lots of people think dS is only metastable and will decay into AdS at some point, or, as you imply, inflation might not be as simple as previously thought; see string gas cosmology/brane gas cosmology.

[Anonymous No.9984184]

>>9984148
>>9984168

This guy knows what he is talking about.

Note that even supersymmetry at Planck scale is more likely than no supersymmetry, so string theory requiring supersymmetry is not an argument against it. Hierarchy problem is not the only reason for supersymmetry.

[Anonymous No.9984326]

>>9982179
>the Ultimate Meme
Lrn2meme fgt pls

[Anonymous No.9984332]

>>9982179

You dare to insult the P H E N O T Y P E D one?

[Anonymous No.9984528]

>>9984148
>String theory makes plenty of predictions, they're just at such high energies that we can't test them right now.
can you show me a calculation of some string theory prediction that gives me some observable signal (above the standard model "background") at some energy that might be observable in future experiments, like at 100 TeV or 500 TeV? (these might be possible in the next 100 years) or 100,000 TeV? (this might be possible in a millennium perhaps)
or, alternatively, can you calculate for me the minimum energy at which we could observe your signal?

i suspect the answer is "no, we can't calculate anything like that yet" and the only things you're talking about are at or near the planck energy -- 10^16 TeV, which means humans will never be able to detect what you're talking about.

it's interesting that you mention these "plenty of predictions" but don't even say what they are. i guess this is string theorist sleight-of-hand: even if we had evidence of string theory, even if we got real great measurements at the FCC, i'm pretty sure the stuff you're referring to wouldn't be in the realm of science, similar to how wormholes and einstein rosen bridges are "predicted" by GR but do not exist, thus they are not observable, and thus they're not scientific in the strict sense. (a diehard empiricist like me would say they purely hypothetical and only of interest mathematically)

> Indeed, it makes perfect sense for SUSY to be broken at the only natural scale in ST, the string scale (near the Planck scale).
i'm pretty sure most string theorists really liked the idea of SUSY breaking at the TeV scale until recently, and you're just a victim of them constantly shifting their goal posts in believing what you say

>It might be possible to rule loads of these out, ...
that would be nice. how much progress has been made on this? will it take another 50 years of taxpayers funding you guys, while we wait for you to provide even one measurable prediction?

pic related

[Anonymous No.9984736]

>>9984528
>can you show me a calculation of some string theory prediction that gives me some observable signal
I'm a different guy but I have a few words on this. For one thing ST does at the very least teach us more about high energy physics. Things like T-duality, S-duality, and so on are quite important to the field. Even beyond that the Ads/CFT correspondence, and the more general gauge/gravity duality and holography, have stringy origins and are incredibly important for theoretical physics. Likewise many heuristics in ST have led to other new discoveries like the fact that you can think of Yang-Mills as the "square root of gravity" and the first actual calculations of black hole entropy directly from stat mech. Nature also holds no obligation to be testable, why we really, really want it to be, it's very likely that many things may just be unreasonably difficult to test. This is one of the reasons that consistency results and the development of so many new tools has been the selling point of ST for a while now. Many of these tools have been successfully applied to other fields like condensed matter physics and even QCD which gives credence to these ideas. Frankly, any theory of quantum gravity will be really hard to test due to the weak nature of gravity, which is why there are various conjectures that seek to prove it's the only consistent theory of QG that we can have in our universe. It is a touch unsatisfying, but it is a possibility. But maybe that's not true, with LIGO and eLISA up and running it may be possible to finally detect some of these effects. ST also hasn't been fully understood, so it's very possible there are some other sharp predictions that could be testable, but it's a beast of a theory that's still not fleshed out. As for the 10^500 that's not really a problem, the parameter space for QFTs is infinite.

[Anonymous No.9984740]

>>9984528
>>9984736
>i'm pretty sure most string theorists really liked the idea of SUSY breaking at the TeV scale until recently, and you're just a victim of them constantly shifting their goal posts in believing what you say
I'm actually gonna say that probably happened for sociological reasons rather than purely scientific. People were realty giddy about the LHC so they may have been to quick to call things. The LHC and experiments to detect proton decay haven't ruled out all forms of SUSY and the mass of Higgs doesn't rule out the possibility either. Neutrino oscillations have shown that physics beyond the standard model exists and a facet of these new theories are the existence of SUSY, so I wouldn't count it out yet. Rather than moving the goal posts I'd say people were to eager and are now looking at things more objectively.
>>9984528
>that would be nice. how much progress has been made on this? will it take another 50 years of taxpayers funding you guys, while we wait for you to provide even one measurable prediction?
For one thing, string theorists and theorists in general are pretty fucking cheap. They don't themselves need money for experiments, they just need paper, a pencil, and a waste basket. They also keep their jobs because, again, there are many uses for the results they bring, both physical and mathematical. Many string theorists also work on more generic problems in high energy physics and even cosmology, people like Witten, Maldacena, Strominger, and so on.

[Anonymous No.9984753]

quantum loop gravity > string theory

[Anonymous No.9984768]

>>9982179
No, if ST ultimately turns out to be completely wrong it raises a few questions. There are two methods one can use to reach ST, first you can try and obtain high energy corrections to gravity in the same way people did to the Weak force. In the latter case we got the Higgs boson, in the former we got ST. As Weinberg points out at every opportunity he gets, gravity is just a spin 2 theory, so there really shouldn't be any reason why our techniques work so well in all cases except gravity, at least from this perspective. Another way to get to ST is through a very modest generalization of QFT. The procedure to just to build a model of quantum gravity and you naturally get ST falling out. In both cases it comes free of ultraviolet divergences and equipped with dualities which is cool and useful and needed.

[Anonymous No.9984776]

>>9984528
>can you show me a calculation of some string theory prediction that gives me some observable signal (above the standard model "background") at some energy that might be observable in future experiments
>i suspect the answer is "no, we can't calculate anything like that yet" and the only things you're talking about are at or near the planck energy -- 10^16 TeV, which means humans will never be able to detect what you're talking about.
Not the same guy but you have, for example, https://arxiv.org/pdf/1112.1059.pdf, where the mass of the Higgs. Note that the mass of the Higgs is an input of the Standard Model, not a prediction of it.

[Anonymous No.9984777]

wtf does it mean when dimensions are compacted? does that mean that the available range of variation in that dimension is so small that we can barely notice it's happening?

[Anonymous No.9984779]

>>9984776
>where the mass of the Higgs
*is predicted.

>>9984777
That they are like a circle with a very small radius, like in Kaluza-Klein theory.

[Anonymous No.9984782]

>>9984779
>like in Kaluza-Klein theory.
i have no idea what that is

[Anonymous No.9984806]

>>9984782
This is an old idea to get general relativity and electromagnetism at the same time from 5-dimensional general relativity. The photon appears as the metric with one component in the compactified dimension.

[Anonymous No.9984918]

>>9984806
so is there any kind of physical analogy for what it means to have a dimension in a small circle?

[Anonymous No.9984923]

>>9984776
this isn’t an example of a prediction of any signal over the SM background

plus it’s about 6-10 years past it being a novel result as far as experiment is concerned. plus i don’t trust that gordie didn’t use a little nudge from 20-20 hindsight

[Anonymous No.9984966]

>>9984918
Look at a string, from far away it looks and behaves like a one-dimensional object, but look up close and it you can see it has extra dimensions. Basically that.

[Anonymous No.9985061]

>>9984923
>this isn’t an example of a prediction of any signal over the SM background
It's a prediction of something that the SM can't predict.

>plus it’s about 6-10 years past it being a novel result as far as experiment is concerned.
Look at the paper, it's from 6 months before the official announcement. You have been proven wrong and want to move the goalpost.

[Anonymous No.9985444]

>>9985061
well that’s confusing because the text of the paper, instead of the watermark, says “dated august 1st 2018”

anyhow even if it were from early 2012, the experimental constraints on what the mass could have been were already pretty narrow, and people on the experiments new where the peak was well before it reached 5 sigma, and we do chat with theorists every so often.

anyhow i wasn’t proved wrong either way because i asked about an ST signal above the SM background, and this is not an example of such a thing