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arXiv · 1509.04259

Topological charge using cooling and the gradient flow

Constantia Alexandrou·Andreas Athenodorou·Karl Jansen
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Abstract

The equivalence of cooling to the gradient flow when the cooling step $n_c$ and the continuous flow step of gradient flow $τ$ are matched is generalized to gauge actions that include rectangular terms. By expanding the link variables up to subleading terms in perturbation theory, we relate $n_c$ and $τ$ and show that the results for the topological charge become equivalent when rescaling $τ\simeq n_c/({3-15 c_1})$ where $c_1$ is the Symanzik coefficient multiplying the rectangular term. We, subsequently, apply cooling and the gradient flow using the Wilson, the Symanzik tree-level improved and the Iwasaki gauge actions to configurations produced with $N_f=2+1+1$ twisted mass fermions. We compute the topological charge, its distribution and the correlators between cooling and gradient flow at three values of the lattice spacing demonstrating that the perturbative rescaling $τ\simeq n_c/({3-15 c_1})$ leads to equivalent results.

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Constantia Alexandrou, Andreas Athenodorou, Karl Jansen. 2015-09-14. Topological charge using cooling and the gradient flow. https://doi.org/10.1103/physrevd.92.125014

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