The gradient flow running coupling scheme

@inproceedings{Fodor2012TheGF,
  title={The gradient flow running coupling scheme},
  author={Zolt{\'a}n Fodor and Kieran Holland and Julius Kuti and D{\'a}niel N{\'o}gr{\'a}di and Chik Him Wong},
  year={2012}
}
The Yang-Mills gradient flow in finite volume is used to define a running coupling scheme. As our main result the discrete beta-function, or step scaling function, is calculated for scale change s=3/2 at several lattice spacings for SU(3) gauge theory coupled to N_f = 4 fundamental massless fermions. The continuum extrapolation is performed and agreement is found with the continuum perturbative results for small renormalized coupling. The case of SU(2) gauge group is briefly commented on.