Re: Anti D-branes?

Lubos Motl <[EMAIL PROTECTED]> wrote in message
news:<[EMAIL PROTECTED]>...
> We have dualities between theories in different number of large
> dimensions, too - for example the AdS/CFT correspondence and holography in
> general ;-)

Yes, but here only one of the theories is gravitational.

> The dualities that I meant could be found in 6+1 large dimensions (or
> less) and I did not intend to change their number. The main portion of the
> moduli space with 6+1 large dimensions and 16 supercharges can be
> described as M-theory on K3, or heterotic strings on T^3, or various
> orientifolds of type II theories with the D-branes to cancel the tadpoles
> (or F-theory on K3 cross S^1). All of these things are dual to one
> another.

The F-theory <-> M-theory part is more or less by definition. The
heterotic <-> type II + orientifolds part comes from the S-duality
between type I and SO(32) heterotic. How do you show the
M-theory on K3 <-> heterotic strings on T^3 part? Can you demonstate
directly the duality between type II (without orientifolds) on K3 and
heterotic strings on T^4 (it follows from compactifying both sides on S^1)?
Btw, do we have mirror symmetry for K3?

> ...Most of these points at
> infinity can be interpreted as some sort of decompactification limits.

Cool, so the moduli spaces for different # of large dimensions are "glued"
along the boundaries?

> It is not just the moduli space, we can see that *all physical phenomena*
> of these seemingly different backgrounds of string/M-theory are dual to
> one another.

Reference?

> A funny thing is that if we write the K3 surface as a T^2-fibration, there
> must be a well-defined number of defects - which are singular fibers in
> this case. This is a way to understand the relation between the K3-shapes
> and the orientifold planes and the branes that appear in other
> descriptions.
>
> Yes, classical general relativity would break down at these defects

Would it? K3, as far as I understand, is a smooth manifold, so the defects
must be artifacts of trying to make it into a T^2-fibration, no?

Best regards,
 Squark

------------------------------------------------------------------

Write to me using the following e-mail:
[EMAIL PROTECTED]
(just spell the particle name correctly and change the
extension in the obvious way)