Physicist here. Just wanted to add a little context. Anyone in string theory will tell you that Witten is possibly the greatest physicist that has ever lived. Interestingly he's completely unknown to the general public.
My layperson's impression is that string theory implies supersymmetry and supersymmetry doesn't easily comport with the latest accelerator results.
Exact Lorentz is a very successful experimental prediction of string theory.
> My layperson's impression is that string theory implies supersymmetry and supersymmetry doesn't easily comport with the latest accelerator results.
Symmetry breaking.
https://en.wikipedia.org/wiki/Supersymmetry_breaking_scale implies LHC was expected to show evidence of supersymmetry. That's what I was thinking of by 'easily'.
Anyway, I guess you are saying he's the greatest ever because of string theory? And we'll just have to see if that pans out as physics.
Moving goal posts. First you asked for predictions, now you're asking for "new" predictions.
Anyway, what does "new" even mean? Some theories say it holds, some theories says it doesn't. String theory says it does, and it's correct.
I think I'm using a well-accepted understanding of science which I'd taken for granted, instead of moving any goalposts. A theory retrodicts some of the same phenomena as its parent theory, as an assumption: that's not evidence that the new theory is more true than the old theory. What I started the thread with was an operationalization of "what if string theory is not true?" It's not a perfect one: string theory could also become accepted as true by finding a way to make it retrodict only things already observed, but with a less complex theory than the standard model. But come on, we're very far from there.
Betcha experimentalists would disagree.
You know, in some sense experimental physics used to be "ahead" of theoretical physics. I accidentally put some current next to a compass and it moves. Why, no one knows.
I would say from 1905 onwards theoretical physics has been ahead of experimental physics. I have reasons to believe X, and a few years later experimentalists verify it. This difference is getting larger very fast. It took from 1933 when neutrinos were postulated by Fermi to being discovered in 1956. It took about 40 years from Higgs suspecting an extra particle was needed to it being found in experiments.
Fast forward 20+ years, and he is working on modeling semiconductor growth (like I was to a degree), and I am long gone from physics. Skipped postdoc/tenure track to go into industry post Ph.D.
My impression dealing with HEP folks for many years, is that a fairly large fraction of folks in the field look down on the rest of the world. Similar with the nuclear people. This is anecdotal of course, and a small subjectively interpreted sampling.
All that said ... One of the more interesting aspects of string theory is that it appears to have analogues and applications in superfluidity, and other phenomenon where you get spontaneous symmetry breaking[1], or where you have critical exponents and length scales[2].
[1] https://arxiv.org/abs/1507.05635
[2] https://www.cambridge.org/core/books/string-theory-methods-f...
- Solid state physics. There are entire fields which are not understood theoretically such as high temperature superconductivity
- Astronomy: dark matter and dark energy. There is no widely accepted theoretical model for both. Both where not predicted by any theory, either.
Saying that theory is ahead of experiment also suffers from survivorship bias. We tend to forget the theoretical predictions that didn't pan out. If the theoretical side predicts 10 different possibilities and the experiments eventually find that one of those is right, that's not evidence that theory is ahead of experiment. We also tend to interpret correct theoretical predictions in a more rosy light after the fact. One of the poster childs for theoretical predictions is the positron. It is said that Dirac predicted the positron, which is true. He first considered that an electron could be in a positive and negative state, but retracted that position later and said that the positive charges were holes in an infinite negative sea, and he theorised that the proton is a negative electron. He was eventually convinced by Oppenheimer that the infinite negative sea idea didn't make sense, and that's when he predicted that there was a positron particle in 1931. But the positron had already been observed two years earlier, although those observations weren't conclusive and the conclusive experiment was done in 1932. The interplay between theory and experiment is often nuanced.