Comparison of different lattice definitions of the topological charge
  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. 
Krzysztof Cichy, Arthur Dromard, Elena Garcia-Ramos, Konstantin   Ottnad, Carsten Urbach, Marc Wagner, Urs Wenger, Falk Zimm...
hep-lat