Sunday, March 16, 2008

The renormalization of G

New paper! Can the scale of quantum gravity be deduced from simple dimensional analysis using low-energy inputs like Newton's constant (G), Planck's constant (hbar) and the speed of light (c)? This leads to the usual estimate of 10^19 GeV for the Planck scale. But it's also possible that renormalization effects (i.e., significant renormalization group evolution of Newton's constant at short distances) cause the true energy at which quantum gravity becomes strong to differ substantially from the naive estimate of 10^19 GeV. We analyze this possibility in the paper. There is an interesting connection to Dvali's work on solving the hierarchy problem by introducing a large number of new particles with conserved charges. He argues that unitarity of black hole evaporation would then require a drastically reduced Planck scale, and our results agree.

arXiv:0803.1836 (hep-th)

Quantum gravity at a TeV and the renormalization of Newton's constant

Xavier Calmet, Stephen D. H. Hsu, David Reeb

We examine whether renormalization effects can cause Newton's constant to change dramatically with energy, perhaps even reducing the scale of quantum gravity to the TeV region without the introduction of extra dimensions. We examine a model which realizes this possibility, and describe experimental signatures from production of small black holes.

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