Strict Inequality for Phase Transition between Ferromagnetic and Frustrated Systems
Emilio De Santis, University of Roma "La Sapienza"
Abstract
We consider deterministic and disordered frustrated systems in
which we can show some strict inequalities
with respect to related ferromagnetic
systems. A case particularly interesting is the
Edwards-Anderson spin-glass model in which it is possible to
determine a region of uniqueness of the Gibbs measure, which is strictly larger than the
region of uniqueness for the related ferromagnetic system. We analyze
also deterministic systems with |JB
| in [JA,
JB], where
0< JA
le JB
< infty , for which we prove strict inequality for the
critical points of the
related FK model.
The results are obtained for the Ising models but some
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