Summing bulk quantum numbers with Monte Carlo in spin foam theories

Summing bulk quantum numbers with Monte Carlo in spin foam theories

Pietro Dona, Pietropaolo Frisoni
The University of Western Ontario and Rotman Institute for Philosophy

Preprint

Publication

ABSTRACT

We introduce a strategy to compute EPRL spin foam amplitudes with many internal faces numerically. We work with texttt{sl2cfoam-next}, the state-of-the-art framework to numerically evaluate spin foam transition amplitudes. We find that uniform sampling Monte Carlo is exceptionally effective in approximating the sum over internal quantum numbers of a spin foam amplitude, considerably reducing the computational resources necessary. We apply it to compute large volume divergences of the theory and find surprising numerical evidence that the EPRL vertex renormalization amplitude is instead finite.