Zoom Quilt for a while (click on "Flash"), T-duality seems a lot less strange to me.

In string theories, there is a duality between large and small distances (T duality)... if you interchange them then you haven't really changed anything physical, but the interpretation of various quantities changes. So if you were to zoom in far enough, just before you got near the Planck scale, you would end up inadvertently zooming out. And you could just as easily see the zooming in as zooming out if you change your interpretation of what's going on. Whenever you're zooming in in one universe, you're zooming out in a dual universe where "drink me" means "eat me" (to put it in Alice in Wonderland terms) and there's no real difference other than the switched meanings. This is a much weirder picture than what's provided by the loop quantum gravity folks who just take the "naive" approach that the Planck length is a discrete unit for space. I still don't really understand it, but the zoomquilt helps me at least feel like it could be consistant.

The zoomquilt is similar in that if you zoom in far enough you end up back where you started... but it's different from string theory in that you're always cyclicly zooming in rather than getting turned around so that you find yourself zooming back out.

I've been itching to make a post about what I'm working on this summer (Matrix Theory), but I feel like I should wait until I get a bit further to try to explain it. I'm just getting to the point where I understand it well enough to write some stuff down. But I'm not ready yet to start doing the main part of it, just some "warm up" calculations to get more comfy.

I have to say, that after viewing this In string theories, there is a duality between large and small distances (T duality)... if you interchange them then you haven't really changed anything physical, but the interpretation of various quantities changes. So if you were to zoom in far enough, just before you got near the Planck scale, you would end up inadvertently zooming out. And you could just as easily see the zooming in as zooming out if you change your interpretation of what's going on. Whenever you're zooming in in one universe, you're zooming out in a dual universe where "drink me" means "eat me" (to put it in Alice in Wonderland terms) and there's no real difference other than the switched meanings. This is a much weirder picture than what's provided by the loop quantum gravity folks who just take the "naive" approach that the Planck length is a discrete unit for space. I still don't really understand it, but the zoomquilt helps me at least feel like it could be consistant.

The zoomquilt is similar in that if you zoom in far enough you end up back where you started... but it's different from string theory in that you're always cyclicly zooming in rather than getting turned around so that you find yourself zooming back out.

I've been itching to make a post about what I'm working on this summer (Matrix Theory), but I feel like I should wait until I get a bit further to try to explain it. I'm just getting to the point where I understand it well enough to write some stuff down. But I'm not ready yet to start doing the main part of it, just some "warm up" calculations to get more comfy.

## Comments

(Anonymous)This dual universe makes no sense. How can you be zooming out in a universe you're not even in? That sounds like a mathematically elegant kludge if you ask me.

Hurry up and figure that stuff out. I want to read about it. :)

spoonlessIf forces act differently at very small scales, do they act differently at very large scales too?

Not if by "large scales" you mean further away from the Planck scale. Things start to work weirdly as you get closer to the Planck scale... it's just that you could see getting closer as getting smaller or getting larger. I think. And actually, I'm cheating a bit here since it's really the string scale that gets involved in T duality, which is not exactly the Planck scale. But compared to us they'd be in the same direction.

Is there something like the planck length only its the "largest" distance?

Well, if you're viewing things in the dual way, then it would be the Planck scale itself. But again, if by large you mean in the

otherdirection... then maybe the Hubble horizon, beyond which we can't see. But I don't know whether that counts, because you could maybe argue there might be stuff beyond that and it's just hidden from us.This dual universe makes no sense. How can you be zooming out in a universe you're not even in? That sounds like a mathematically elegant kludge if you ask me.

Well I think the point is that you can't tell which of the two you're really in because they're both valid descriptions for the same thing. It could be that it's just a mathematical kludge, but it could also be that our previous attempts at mathematically modelling geometry (Euclid, Reimann, etc.) were too simplistic. Which is what the string theorists seem to be saying here.

spoonlessInstead of considering it as two dual universes, which is probably misleading... think of it as one universe where space is like an hourglass. The Planck scale is the nexus of the hourglass, and we're in one of the lobes. There's no way to tell which lobe we're in because they're identical, and for the same reason there's also no way to tell which way is up and which way is down. Does that make more sense?

troyworks