If you don't already have a lot of background in this area, you should not expect to understand it. He is assuming that a lot of theoretical claims which, as far as I know, are not definitely established (many of them can't even be tested at all experimentally), are true, and working out a particular implication. But without a detailed understanding of all those theoretical claims, it's going to be hard to make sense of this letter. I don't follow all of it myself since I'm not familiar with all of the literature he is referring to.I do not fully understand his letter or the claim that he is making.
I agree. But it might? fit a little better into btsm?Ehm, doesn't this fall under "personal speculation" and thus shouldn't be discussed here, although the speculation comes from a quite famous physicist? SCNR
Agree. Mods would you please move it to "Beyond the Standard Model" forum?I agree. But it might? fit a little better into btsm?
I don't think it's just personal speculation; the models Susskind is referring to are models that have been published in peer-reviewed papers and are used in a lot of ongoing research. But it was correctly pointed out that the topic does belong in the Beyond the Standard Model forum, so I have moved this thread there.doesn't this fall under "personal speculation" and thus shouldn't be discussed here, although the speculation comes from a quite famous physicist?
I think a better wording is "some already thought it from the 70's and 80's" (also related to your following post). Perhaps Susskind would say that recent theoretical developments (e.g. AdS/CFT, ER=EPR) provide more support for the idea that classical GR follows from quantum strings.That's nothing new, we already know it from the 70's and 80's.
In the sense of string theory being a set of nice mathematical ideas with no experimental evidence for, and in the sense of string theory seeming messy and incomplete (as compared to, for example, clean and consistent general relativity), I understand why one can think of string theory as not-even-wrong fashionable nonsense. But I believe some recent developments, e.g. the applications of AdS/CFT to condensed matter and nuclear plasma, indicate that the mathematics of string theory does relate to things that can be measured in the lab. Here, Susskind is proposing experiments, based on more powerful quantum computers that could be developed some day.In the past, string theory has been accused for being not even wrong. I am afraid that some modern trends could be characterized as something even worse, like fashionable nonsense
Yes but not the same spacetime. The CFT lives on the boundary, and has info on the structure of spacetime in the bulk.if you write down the Feynmandiagrams of a CFT like N=4 Super YM, somewhere deep down in those diagrams there is information about the structure of spacetime itself hidden.