Dyons and Roberge - Weiss transition in lattice QCD

Understand

We study lattice QCD with $N_f=2$ Wilson fermions at nonzero imaginary chemical potential and nonzero temperature.

• We relate the Roberge - Weiss phase transition to the properties of dyons which are constituents of the KvBLL calorons.
• We present numerical evidence that the characteristic features of the spectral gap of the overlap Dirac operator as function of an angle modifying the boundary condition are determined by the $Z_3$ sector of the respective imaginary chemical potential.
• We then demonstrate that dyon excitations in thermal configurations could be responsible (in line with perturbative excitations) for these phenomena.