Volker Bach and Jacob Schach Moller
Correlation at low temperature: II. Asymptotics
(114K, latex)

ABSTRACT.  The present paper is a continuation of our paper 
[Bach-Moller mp_arc 02-215] where the truncated two-point correlation function for a class of lattice spin systems was proved to have exponential decay at low temperature, under a weak coupling assumption. In this paper we compute the asymptotics of the correlation function as the temperature goes to zero. This paper thus extends [Bach-Jecko-Sjostrand, mp_arc 98-552] in two directions: The Hamiltonian function is allowed to have several local minima other than a unique global minimum, and we do not require translation 
invariance of the Hamiltonian function. We are in particular able 
to handle spin systems on a general lattice.