Comment on "Six-state clock model on the square lattice: Fisher zero approach with Wang-Landau sampling".
Hwang in [Phys. Rev. E 80, 042103 (2009)] suggested that the two transitions of the six-state clock model on the square lattice are not of the Kosterlitz-Thouless type. Here we show from simulations that at the upper transition, the helicity modulus does make a discontinuous jump to zero. This gives strong evidence for a Kosterlitz-Thouless transition.
Baek
Seung Ki
SK
Department of Physics, Umeå University, 901 87 Umeå, Sweden.
Minnhagen
Petter
P
Kim
Beom Jun
BJ