A two-dimensional Ising model with non-universal critical behaviour

Kazuhiko Minami, Masuo Suzuki

R. Z. Bariev, Ingo Peschel

Kazuhiko Minami, Masuo Suzuki

Kazuhiko Minami, Masuo Suzuki

K Minami, Masuo Suzuki

Two conditions are derived for Ising models to show non-universal critical behaviour, namely, conditions concerning (i) logarithmic singularity of the specific heat and (ii) degeneracy of the ground state. These conditions are satisfied by the eight-vertex model, the Ashkin-Teller model, some Ising models with short- or long-range interactions and even Ising systems without the translational or rotational invariance.

Kazuhiko Minami, Masuo Suzuki

PACS number: 05.50 Two conditions are derived for Ising models to show non-universal critical behaviour, namely conditions concerning 1) logarithmic singularity of the specific heat and 2) degeneracy of the ground state. These conditions are satisfied with the eight-vertex model, the Ashkin-Teller model, some Ising models with short- or long-range interactions and even Ising systems without the translational or the rotational invariance. 1 § 1