Would asymptomatic safe gravity grow weaker like QCD?

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The discussion centers on the concept of asymptotic safety in quantum gravity (QG) and its potential parallels with quantum chromodynamics (QCD). Participants explore whether gravity, like QCD, could exhibit weaker interactions at higher energies, contradicting classical general relativity (GR) predictions. Key references include a review paper indicating that as the wave number k approaches infinity, the dimensionful Newton constant vanishes while the cosmological constant diverges. The implications of this theory raise questions about the compatibility of weak interactions at high energy with the holographic principle.

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kodama
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QCD is asymptomatic safe well known to grow weaker at higher energies.

if gravity is also asymptotic safe would it grow weaker at higher energies instead of stronger as predicted by classical GR?

if not, is it possible there is a quantum gravity theory that like QCD grows weaker at higher energies?

i.e at low energies it is described as GR, but at high energies it is QCD-like and grows weaker

QCD-gluons and gravitons are non-abelian self-interacting bosons
 
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As far as I understand the proposal, what one requires is that the system approaches a UV fixed point at high energies. The fixed point could be non-interacting but generically I would expect some order one dimensionless interaction strength. Although I haven't thought carefully about it, I would guess that in the case of gravity one could argue against weak interactions at high energy as incompatible with the holographic principle.

EDIT: More generally, I don't understand much about how non-perturbative aspects of gravity - black holes, holography, etc. - are supposed to work in the asymptotic safety scenario.
 
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kodama said:
..
if not, is it possible there is a quantum gravity theory that like QCD grows weaker at higher energies?
In partial answer, in the most recent review paper I know of on AsymSafe QG, on page 36 it says
==quote http://arxiv.org/pdf/1202.2274.pdf ==
Hence for k → ∞ and d > 2 the dimensionful Newton constant vanishes while the cosmological constant diverges.
==endquote==

The parameter k is like a wave number, an inverse length. So for low k (the IR or coarse scale) the Newton constant G and the cosmo constant Λ are the usual G and Λ.

A commonly discussed form of the theory concerns dimensionless versions gk and λk which approach a fixed point g*, λ*

As for the dimensionful versions, Gk = gk/k2 goes to zero as g*/k2 and Λk = λkk2 diverges as λ*k2
 
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Physics Monkey said:
As far as I understand the proposal, what one requires is that the system approaches a UV fixed point at high energies. The fixed point could be non-interacting but generically I would expect some order one dimensionless interaction strength. Although I haven't thought carefully about it, I would guess that in the case of gravity one could argue against weak interactions at high energy as incompatible with the holographic principle.

EDIT: More generally, I don't understand much about how non-perturbative aspects of gravity - black holes, holography, etc. - are supposed to work in the asymptotic safety scenario.

maybe the holographic principle is wrong?
 

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