The SU (3) twisted gradient flow strong coupling without topology freezing

We investigate the role of topology in the lattice determination of the renormalized strong coupling via the gradient flow. This is done adopting the Parallel Tempering on Boundary Conditions to deal with the infamous topological freezing problem that affects standard local updating algorithms. We show that, even in the presence of severe topological freezing, both algorithms yield the same strong coupling once projected onto a fixed topological sector. Moreover, we show that using a non-projected definition of the coupling leads to the same step-scaling sequence. This means that projecting the coupling onto a fixed topological sector does not affect the determination of the dynamically-generated scale of the theory.