We prove the existence of new Griffiths type inequalities for anti-ferromagnetic Ising spin systems and the corresponding lattice gases. It is shown in particular that for such a system the two spin (or particle) Ursell function [〈σiσj〉 - 〈σi〉 〈σj〉] is positive when i and j are on the same sublattice and negative when they are on different sublattices. This is true for all values of the external magnetic field (or chemical potential) at the different lattice sites.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)