Could bosonic strings be a kind of projective space of m-theory?

[MTd2]

Just like you can create the ilusion of superluminal motion by projecting a flashlight into a wall, some strings would be projected into tachyons. Has anyone heard or thought about that?

 

[BenTheMan]

How would this work?

The theories live in different space-time dimensions.

 

[MTd2]

The theories live in different space-time dimensions.

That's why I am saying projections. Hmm, I guess it would be better if I say compactifications on some kind of projective space.

 

[BenTheMan]

Ahh I see.

So you want to compactify 15 of the 26 dimensions of bosonic string theory and get M theory?

 

[BenTheMan]

I think that would not be good, though because it would say that bosonic string theory is more fundamental that Mtheory, which we know is probably not true.

I'd be willing to bet it doesn't work. You'd have to explain why Mtheory knows about SUSY and bosonic string theory doesn't. You'd have to explain what happens to the tachyon (it could get projected out, but who knows?).

 

[MTd2]

Quite the contrary. Susy is another motivation, that's why I am said m-theory. Do you know any case of getting non commutative spinors from the compactification of bosonic fields?

 

[BenTheMan]

Why is SUSY a motivation?

 

[MTd2]

I'd like to see if it is possible to explain the fermions by geometric means, instead of just being a field on the worldsheet.

 

[kneemo]

So you want to compactify 15 of the 26 dimensions of bosonic string theory and get M theory?

Or better yet, fiber a 16-dimensional projective space over an 11-dimensional M-theory base.

arXiv: 0909.4737

 

[suprised]

I'd like to see if it is possible to explain the fermions by geometric means, instead of just being a field on the worldsheet.

Yep, that goes under the name "spin from isospin" and can lead to spin 1/2 modes in monopole backgrounds. That goes back to work of Jackiw and Rebbi in the 70s.

And there was even an attempt to make use of this in the bosonic string, back in the eigthies, by Englert, Nicolai & Co. The aim was to get the heterotic string rather than M-Theory. This makes much more sense, not only because M-Theory is a strong coupling limit without world-sheet formulation. The point is that 26-10=16, which would allow to obtain the E8xE8 or SO(32) gauge symmetries by compactification on an 16 dimensional self-dual lattice.

But all attempts, AFAIK, never got further then purely kinematical or group theoretical reasonings. I remember that there was some revived interest in this more recently, but again, I don't think anything concrete ever got out from that idea - so far.