A random assortment of possibly interesting links:
- New videos from the IHES include new interviews, and talks from the recent Ofer Gabber conference. If you want to know more about prisms than what you can get from the video here, I hear rumors that Bhargav Bhatt will be our Eilenberg lecturer this fall at Columbia.
- Another talk at the Gabber conference was the latest on local (quantum) geometric Langlands from Gaitsgory. Also on this topic, there’s a July 4 preprint from Arakawa and Frenkel (advertised here).
- John Horgan has an interview with Jim Holt, headlined Why Does Jim Holt Exist?. For reviews of Holt’s two most recent books, see here and here.
- For two interesting blog posts from HEP experimenters about news from their field, see Jonathan Link at SciAm on neutrinos, and Tommaso Dorigo on the Higgs self-coupling. Dorigo’s posting is the more technical one, explaining a new CMS result bounding the Higgs self-coupling.
The LHC experiments still seem to be a long ways away from actually measuring the Higgs self-coupling, but may be able to do so in future higher-luminosity stages of the LHC program. The Higgs remains the least understood part of the SM, responsible for most of the undetermined parameters of the theory. Any measurement of its self-interactions is an important goal.
While it often seems that experimental results relevant to going beyond the Standard Model are inaccessible due to the necessity of higher energies, these two blog posts point to important open questions about the SM that are hard to study not because of fundamental limits on collision energies, but because of small event rates and high backgrounds.
- The question recently came up here (see this posting) of how good the SUSY GUT coupling constant unification prediction is. At a recent summer school lecture, Ben Allanach says the prediction is off by 5 sigma, i.e. that if you try and predict the strong coupling at the Z mass this way, you get 0.129 +/- 0.002, whereas the measured value is 0.119 +/- 0.002. Someone should tell Frank Wilczek…
Update: For more on the dS vacua issue, see this blog posting by Ulf Danielsson. Danielsson refers to criticism of the landscape at my blog, but ignores the point I’ve often made that string theory is in just as much trouble if the advertised dS vacua don’t exist, since then it has no known way to connect to the real world and its positive CC. Somehow he sees this as a virtue, that “These are exciting times”, which I find mystifying.
He also claims that, all is well, since:
By studying the mathematics of the theory we will find out what it predicts, and by comparing with observations we will learn whether it has anything to do with reality.
But the underlying problem here is that the mathematics of the theory is unknown. Read the responses above from two experts to the question of why this issue has not been conclusively determined. Neither of them present any possibility of a conclusive determination. For both of them, this is about weighing the plausibility of various conjectures about possible solutions to unknown conjectural equations. At this point I seriously doubt it is possible for this to be resolved one way or the other.
Update: ICHEP 2018 is winding up, talks available here. There was one plenary summary talk on “Formal Theory Developments”, by Tadashi Takayanagi. It begins by promoting string theory, then goes on to address the problem of how it relates to fundamental physics with:
However, please do not ask me questions like:
How to derive Standard Model from string theory?
Why do we live in 4 dimensions?
How to realize de-Sitter spacetimes in a well-reliable way?
String theory is still too infant to give complete answers to them.
The “complete” is intentionally misleading, since string theory now gives no answers at all to these questions. While celebrating the 50th anniversary of string this year, it seems that “string theory is too new an idea to evaluate” is the standard answer to anyone who points out its failures.