- #1
S.Daedalus
- 221
- 7
I just recently came across this idea, outlined in http://arxiv.org/abs/1005.3497" ). I've looked for some discussion here, but couldn't find any, so I thought I'd start one (if I missed some previous discussion, I'd appreciate a link).
The basic idea is simple: to probe transplanckian physics, one needs to concentrate an energy [tex]E > 1/L[/tex] into a spacetime volume of size [tex]L[/tex]. The Schwarzschild radius of this configuration is [tex]R(L) = L_{p}^2/L[/tex], with [tex]L_{p}[/tex] being the Planck length. Thus, for [tex]L < L_{p}[/tex], a black hole forms, hiding all potentially new physics within its event horizon.
This BH is essentially a (semi-)classical object, which becomes more and more classical (i.e., larger) the harder you try to probe the sub-Planck scale; hence, attempts to probe the deep-UV limit of the theory bounce back to the IR, which is of course well described by the existing theory -- physics on sub-Planck scales just never plays any role at all. Hence, since quantum gravity stays sane up to the Planck length, and the theory just curls back in upon itself on lengths smaller than that, it is essentially self-complete.
So, what's everybody's thoughts on this? Personally, I'm refraining from forming an opinion for the moment, on account of not being informed enough -- which I hope some discussion here will remedy. But I'm definitely intrigued, and I do wonder somewhat that this doesn't seem to have generated more buzz...
The basic idea is simple: to probe transplanckian physics, one needs to concentrate an energy [tex]E > 1/L[/tex] into a spacetime volume of size [tex]L[/tex]. The Schwarzschild radius of this configuration is [tex]R(L) = L_{p}^2/L[/tex], with [tex]L_{p}[/tex] being the Planck length. Thus, for [tex]L < L_{p}[/tex], a black hole forms, hiding all potentially new physics within its event horizon.
This BH is essentially a (semi-)classical object, which becomes more and more classical (i.e., larger) the harder you try to probe the sub-Planck scale; hence, attempts to probe the deep-UV limit of the theory bounce back to the IR, which is of course well described by the existing theory -- physics on sub-Planck scales just never plays any role at all. Hence, since quantum gravity stays sane up to the Planck length, and the theory just curls back in upon itself on lengths smaller than that, it is essentially self-complete.
So, what's everybody's thoughts on this? Personally, I'm refraining from forming an opinion for the moment, on account of not being informed enough -- which I hope some discussion here will remedy. But I'm definitely intrigued, and I do wonder somewhat that this doesn't seem to have generated more buzz...
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