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June 20, 2009
Instiki 0.17
We’ve just released Instiki 0.17, with a number of interesting new features, and a ton of bug fixes.
Among the new features,
- Ability to rename pages
Ability to redirect Wikilinks, using
[[!redirect …]]
- HTTP 301 redirects, for redirected/renamed pages
I should like to thank Json Blevins, Ari Stern, and the crew at ncatlab.org for their feedback, bug reports, and remorseless testing. I wouldn’t (indeed, couldn’t) have done it without them.
June 19, 2009
Synchronicity
I was visiting the University of Michigan earlier this Spring, where Gordy Kane told me a story. He’d recently given a public lecture, and was somewhat taken aback when, during the question period afterwards, he was asked about the status of Garrett Lisi’s Theory of Everything. The questioner was convinced that Lisi was a key player in the unification 'biz, and was surprised that his theory had not received more attention (which is to say, had not been mentioned at all) in Gordy’s talk.
The very same day, I received an email from a mathematician working in Representation Theory. He was disgruntled that his student was being asked about Lisi’s work in the course of job interviews. He knew I had some blog posts about Lisi’s “theory”, but had I written these up anywhere? I responded that I didn’t see how it could possibly be worthwhile to publish a “refutation” of an unpublished work. And, in any case, what I had done was of such a mind-numbingly trivial nature that no respectable journal (in either Math or Physics) would consent to publish it. But Skip insisted that it would be helpful to someone like his student to be able to cite a paper in which this stuff had been debunked.
By coincidence, an exchange of comments, with the man himself, at the at the n-Category Café, convinced me that my blog posts have been less than efficacious.
So I decided to take Skip up on his suggestion and try to distil the arguments of the aforementioned blog posts and strengthen them into a theorem that some (not necessarily self-respecting) Math journal might publish.
June 18, 2009
When in Rome …
Anyone up for dinner Saturday night?
I’m staying a few blocks west of Termini. I may be a bit jetlagged, but promise witty repartee, to the extent I am able.
Akulov-Volkov Redux
One of the least penetrable chapters of Wess & Bagger is the chapter on nonlinear realizations of supersymmetry, AKA the Akulov-Volkov formalism. Nati Seiberg gave a lecture (based on joint work with Zohar Komargodski) about a new approach to the subject, which seems much simpler. Of course, anything he can do should also be possible in the AV formalism. But many things are much more transparent in his formalism than in theirs.
June 17, 2009
Penrose Diagram Follies
Gary Horowitz gave a beautiful talk, on Tuesday, about his work with Evan and Albion on a holographic model of blackhole formation and evaporation in AdS.
It’s a very nice paper, which discusses a 5-dimensional generalization of BTZ blackholes, which can be studied (seemingly reliably), in AdS/CFT.
But I got somewhat annoyed when he he threw up a slide of figure 4 in their paper
June 9, 2009
Draining the Swampland
Vijay Kumar and Wati Taylor have an interesting paper out, in which they argue that all anomaly-free supersymmetric field theories, coupled to 6D supergravity, can be UV-completed in string theory. Well … umh … that’s a bit of a stretch, but, morally, that’s what they claim.