Comparison of different lattice definitions of the topological charge

Abstract

We present a comparison of different definitions of the topological charge on the lattice, using a small-volume ensemble with 2 flavours of dynamical twisted mass fermions. The investigated definitions are: index of the overlap Dirac operator, spectral projectors, spectral flow of the Hermitian Wilson-Dirac operator and field theoretic with different kinds of smoothing of gauge fields (HYP and APE smearings, gradient flow, cooling). We also show some results on the topological susceptibility.

arXiv comment7 pages, 2 figures, presented at the 32nd International Symposium on Lattice Field Theory (Lattice 2014), 23-28 June 2014, Columbia University, New York, NY, USA

References in corpus (5)

• Perturbative analysis of the gradient flow in non-abelian gauge theories
• Comparison of the gradient flow with cooling in $SU(3)$ pure gauge theory
• Universality of the topological susceptibility in the SU(3) gauge theory
• Lattice QCD with a chirally twisted mass term
• Continuum Limit of Overlap Valence Quarks on a Twisted Mass Sea

Cited by in corpus (5)

• Axion phenomenology and $\theta$-dependence from $N_f=2+1$ lattice QCD
• Cumulants of the QCD topological charge distribution
• Measuring the Topological Susceptibility in a Fixed Sector
• Recent progress on QCD inputs for axion phenomenology
• Theta dependence in the large N limit