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arXiv · 1503.06233

Critical scaling in quantum gravity from the renormalisation group

Kevin Falls
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Abstract

The scaling behaviour of euclidean quantum gravity at an asymptotically safe critical point is studied by means of the exact renormalisation group. Gauge independence is ensured via a specific parameterisation of metric fluctuations introduced in a recent paper. Within a non-perturbative approximation the beta function for Newton's constant takes a simple form to all orders in $\hbar$. A UV fixed point is found to exist for $d\leq 7$ spacetime dimensions at which the critical scaling can be assessed. The critical exponent for the Newton's constant $ν$ is found to be regulator independent close to two dimensions. Applying Litim's optimisation criteria we find $ν\approx 1/3$ in four spacetime dimensions. This value is in agreement with lattice studies supporting the existence of a second order phase transition between strongly and weakly coupled phases.

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Kevin Falls. 2015-11-15. Critical scaling in quantum gravity from the renormalisation group. https://arxiv.org/abs/1503.06233

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