1.2. Potts model In the Potts model, the spin variable i assume q value, as {0, 1, . . . ,q1}. The energy of the

1.2. Potts model In the Potts model, the spin variable σi assume q value, as {0, 1, . . . ,q−1}. The energy of the configurations is given by H = −J

ij

δσi ,σj ,

where δa,b = 1 if a = b 0 if a = b.

a. Identify the symmetry transformations of the spins that leave the Hamiltonian invariant.

b. Show that for q = 2, the Potts model is equivalent to the Ising model.

c. Discuss the configuration of the minimum energy in the anti-ferromagnetic limit J→−∞.