# Quantum fluctations and singularities.

Can one say that it is the same factors (whatever they may be, I don't know) in M-theory/String theory that puts away the effects of quantum fluctations, and also puts away the need/possibility of a singularity in a black hole?

I see a connection since M-theory sets a limit of size (planck- length?), and thus the small but non negliable effects of quantum mechanics on a small scale can be ignored, since string theory sets a smallest limit which is bigger than the level at which quantum fluctations occur.

The same reasoning goes for black hole singularities, though I can't explain that with the details used above.

How are these two factors/effects of string theory connected (do they even exist?).

//Martin

Originally posted by martinrandau
I see a connection since M-theory sets a limit of size (planck- length?), and thus the small but non negliable effects of quantum mechanics on a small scale can be ignored, since string theory sets a smallest limit which is bigger than the level at which quantum fluctations occur.
What? Quantum effects are very important on the Planck scale. (And why should we "ignore" a "non-negligible" effect? Isn't that an oxymoron?)

The same reasoning goes for black hole singularities, though I can't explain that with the details used above.
Is is thought that a fundamental size limit in the form of the Planck length may remove singularities from the theory. It is known that this can happen for some singularities, but the issue of generic black hole singularities is not yet well-understood.

http://arXiv.org/abs/hep-th/0106148

http://arXiv.org/abs/gr-qc/9503062

Originally posted by Ambitwistor
What? Quantum effects are very important on the Planck scale. (And why should we "ignore" a "non-negligible" effect? Isn't that an oxymoron?)

What I meant was that, as string theory sets a smallest level, the fluctations, etc. that hinders General Relativity from working at a sub- planck level no longer exists. Do you know what I mean?

What I meant was that, as string theory sets a smallest level, the fluctations, etc. that hinders General Relativity from working at a sub- planck level no longer exists. Do you know what I mean?
I'm still not sure what you mean. General relativity doesn't work on a Planck scale even in string theory --- it's a fully quantum-gravitational regime. Or did mean that Planck-scale string physics is different from general relativity's predictions for the Planck scale (and below)?