Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Numerical evidence for a phase transition in 4d spin foam quantum
  gravity   Building on recent advances in defining Wilsonian RG flows, and in particular
the notion of scales, for background-independent theories, we present a first
investigation of the renormalization of the 4d spin foam path integral for
quantum gravity, both analytically and numerically. Focussing on a specific
truncation of the model using a hypercubic lattice, we compute the RG flow and
find strong indications for a phase transition, as well as an interesting
interplay between the different observed phases and the (broken) diffeomorphism
symmetry of the model. Most notably, it appears that the critical point between
the phases, which is a fixed point of the RG flow, is precisely where broken
diffeomorphism symmetry is restored, which suggests that it might allow for the
definition a continuum limit of the quantum gravity theory.

33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat