Musings

Delays

If the thunderstorms in Dallas do not totally disrupt my plans (looks like I’ve already missed my original flight to Charles de Gaulle), I should be in Paris sometime tomorrow morning. [Update (from DFW): Yup, missed that flight. My new flight gets into CDG at 11am.]

My agenda for the day involves

1. Check into the hotel and take a well-deserved shower.
2. Around 3pm (8am CDT), avail myself of the free WiFi at the hotel and do a little iChat audio conference with S. and the kids. (So far, only one iSight camera in the family, so no video. )-:)} ) [Correction: There is no “free” WiFi at the hotel; there’s 10€/2 hours WiFi at the hotel, “thanks” to Orange. And the reception is crappy to boot. Gonna have to find something else. Hmmmm … there’s a café right down the street which advertises free WiFi. I wonder what delectables 10€ will buy me there?]
3. At 4 pm, register for Strings 2004 at the École Normale Supérieur.
4. At 5pm; there’s a concert of Islamic Music at the Louvre.

The rest of the day, I’m free. So if you’re in Paris tomorrow, send me an email and maybe we’ll meet up.

In the meantime, I’ve got some time to kill here at Austin-Bergstrom; here are some papers I’m looking at to while away the hour(s).

Katz and Sharpe have been looking at worldsheet instanton corrections to certain correlation function (which correspond to spacetime superpotential couplings) in (0,2) linear σ-models. One of the interesting things that they find is that different linear σ-model presentations of the same bundle lead to different extensions of the resulting sheaves over the compactification of the moduli space of instantons. This is related to an older puzzle, namely that the condition for the cancellation of worldsheet gauge anomalies is typically stronger than the corresponding spacetime condition that $c_2(\mathcal{E})=c_2(T)$. The presentation which solves the worldsheet gauge anomaly cancellation condition is the one to use.

Basu, Green and Sethi note that the holomorphic part of the $N=4$ super-Yang Mills action is in a supermultiplet with the superconformal currents. That implies Ward identities which determine the coupling constant dependence of the correlation functions of operators in short supersymmetry multiplets. They use this to prove nonrenormalization theorems for 2- and 3-point functions.

Karl Landsteiner does the Dijkgraaf-Vafa/Cachazo-Douglas-Seiberg-Witten analysis for $N=1$ supersymmetric theories without adjoint matter.

My colleagues, Aaron and Uday propose Loop-$E_8$ bundles as the topological setting for classifying fluxes in M-Theory/(massive) Type IIA. I’ve talked to them a lot about this, and have gone from thinking that it didn’t make any sense whatsoever to being quite intrigued.