Tuesday, February 27, 2007 ... Deutsch/Español/Related posts from blogosphere

Matrix theory in 9 dimensions

I recommend you a new paper by

about the Matrix theory description of vacua with nine (8+1) flat infinite directions and 16 supercharges. The matrix model is generically a gauge theory on a cylinder. The only case in which it's that simple is the vacuum where the gauge group is broken down to SO(16) x SO(16) by a Wilson line around a circle in N=1, d=10 SUGRA-SYM coupled system - something that you can get both from the SO(32) and E8 x E8 starting points.

Recall that in 10D, the only really simple vacua with a matrix model description were type IIA with 32 supercharges and heterotic string theory with the E8 x E8 gauge group broken to SO(16) x SO(16) by longitudinal Wilson lines with 16 supercharges.

The other points of the moduli space they try to cover involve matrix models (2+1-dimensional generalized gauge theories) where the gauge coupling diverges as you approach one of the boundaries of the cylinder; they confirm the Kabat-Rey construction using a different interpretation. They have also (for the first time) looked at the description of the compactifications of M-theory on the Klein bottle and the Möbius strip, too - which also includes the Dabholkar-Park type IIA background with two different kinds of orientifolds (a perturbative dual of the Klein bottle compactification of M-theory) and the CHL string (the perturbative heterotic limit of the Möbius strip compactification of M-theory, with the exceptional group at level two).

Normally, orientifold O8-planes may coincide with D8-branes. You can keep on removing the D8-branes from the O8-plane, until the number of D8-branes is zero. That's what you would think except that they argue that you can actually remove one more, so that the number of remaining D8-branes on the O8-plane equals minus one. ;-) This O8-plane "in debt" must be infinitely strongly coupled but it still preserves the same supersymmetries. This novel discussion emerges from their unified description of the unoriented compactifications.

Add to del.icio.us Digg this Add to reddit

snail feedback (0) :