The topological susceptibility of SU(3) gauge theory near Tc

We compute the topological susceptibility χt in SU(3) lattice gauge theory using fermionic methods based on the Atiyah–Singer index theorem. Near the phase transition we find a smooth crossover behavior for χt with values decreasing from (191(5) MeV)4 to (100(5) MeV)4 as we increase the temperature from 0.88Tc to 1.31Tc, showing that topological excitations exist far above Tc. Our study is the first large scale analysis of the topological susceptibility at high temperature based on the index theorem and the results agree well with field theoretical methods.