Chaos in the antiferromagnetic Ising spin model
N.S. Ananikian, S.K. Dallakian, N.Sh. Izmailian and K.A. Oganessyan
Yerevan Physics Institute
The three-site antiferromagnetic Ising spin model on Husimi tree in
external
magnetic field is investigated. The quantitative picture of the full
doubling bifurcation diagram, including chaos, for the magnetization of
this
system is exhibited [1]. With "termodynamic formalism" we investigate the
antiferromagnetic Ising model in case of fully developed chaos and
describe
the chaotic properties of this statistical mechanical system via the
invariants characterizing a strange attractor. It is shown that this
system
in chaotic region displays a phase transition at positive
"temperature" 
.