Improved gradient flow for step scaling function and scale setting

Abstract

The gradient flow renormalized coupling offers a simple and relatively inexpensive way to calculate the step scaling function and the lattice scale, but both applications can be hindered by large lattice artifacts. Recently we introduced an empirical non-perturbative improvement that can reduce, even remove $\mathcal{O}(a^2)$ lattice artifacts. The method is easy to implement and can be applied to any lattice gauge theory of interest both in step scaling studies and for scale setting. In this talk I will briefly review this improvement method and discuss its application for determining the discrete $\beta$ function of the 8 and 12 flavor SU(3) systems and for improved scale setting in 2+1+1 flavor QCD

Comments: 7 pages; Contribution to The 32nd International Symposium on Lattice Field Theory, 23-28 June, 2014, Columbia University New York, NY