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complementary, that is, to the cartoon for the black D-branes which I had added a few days back. That must have been in the brief period where the announcement mechanism was not working.
have added this:
But actual checks of the proposal that D-brane charge is given by K-theory, via concrete computation in boundary conformal field theory, have revealed some subtleties:
Stefan Fredenhagen, Thomas Quella, Generalised permutation branes, JHEP0511:004, 2005 (arXiv:hep-th/0509153)
It might surprise that despite all the progress that has been made in understanding branes on group manifolds, there are usually not enough D-branes known to explain the whole charge group predicted by (twisted) K-theory.
finally added the original article
although it appears that we have modified the type II theory by adding something new to it, we are now arguing that these objects are actually intrinsic to any nonperturbative formulation of the type II theory; presumably one should think of them as an alternate representation of the black p-branes
as well as more review texts, such as
The ambition of that book is really nice. Sad that the publisher didn’t bother to have a native English speaker look over it even briefly.
Has the puzzle posed in Section 7.2 here been solved yet?
Undoubtedly late to the party, I recently came across the following paper:
There are at least two claims to be highlighted. First, that there exist “negative branes” (not to be confused with anti-branes) which induce a fermionic Chan-Paton gauge group, in the sense that N D-branes and M negative D-branes is supposed to induce the gauge supergroup U(N|M). Second, that these branes induce a change in the metric signature, thus making the latter dynamic.
I’ve been browsing through the papers that cite this article but I don’t really see anything more precise said about these two claims. Does any of this appear in the Hypothesis H research program? For instance, here super-fluxes are discussed but I don’t think this has to do with anything that would be something like a super K theory that allegedly would classify those branes. And as for the metric signature, we have already seen that different signatures appear in the bouquet (say Remark 3.43 here), but while these are related by T duality, there doesn’t seem to be any sort of negative branes in the corresponding extension algebras, no?
I don’t have anything about “negative branes” in this sense, sorry.
But this reminds me of the somewhat heretic observation that already the hard worldsheet evidence for ordinary SU(N) gauge fields on N coincident D-branes is surprisingly thin, or at least was for a long time after its proposal.
The references that I am aware of are compiled here: the now ubiquituous statement started life as an “evident guess” (sic) by Witten 95 and was immediately promoted to a fact by early citing authors, maybe beginning with Myers 95.
The only two actual checks that I am aware of are Berkovits & Schnabl 2003 and Lee 16, both by SFT methods.
For checking the claimed generalization to “negative branes” one might want to try to generalize these SFT derivations, if possible.
Hmm, I see.
What about the claim of the metric signature as dynamically determined?
I can’t speak to signature change. We touched on this before: Several deep facts about 11D SuGra depend on Minkowski signature, and the brane bouquet that leads up to it predicts Lorentzian signature, which makes the possibility of signature change seem all but excluded, unless possibly in a sense far remote from what is currently understood.
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