Backward running or absence of running from Creutz ratios

TL;DR

This paper investigates the running coupling in SU(2) lattice gauge theory with two adjoint fermions, revealing either backward running or no running at strong coupling, supporting the presence of an infrared fixed point.

Contribution

It provides new lattice-based insights into the nonperturbative running behavior of the coupling in a theory with potential infrared conformality.

Findings

Backward running observed at strong coupling

Absence of running depending on extrapolation method

Supports existence of an infrared fixed point

Abstract

We extract the running coupling based on Creutz ratios in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. Depending on how the extrapolation to zero fermion mass is performed, either backward running or an absence of running is observed at strong bare coupling. This behavior is consistent with other findings which indicate that this theory has an infrared fixed point.