EXACT THERMODYNAMICS OF THE DOUBLE SINH-GORDON THEORY IN 1-DIMENSIONS(1)

We study the classical thermodynamics of a (1 + 1)-dimensional double- well sinh-Gordon theory. Remarkably, the Schrodinger-like equation res ulting from the transfer integral method is quasi-exactly solvable at several temperatures. This allows exact calculation of the partition f unction and some correlation functions above and below the short-range order (''kink'') transition, in striking agreement with high resoluti on Langevin simulations. Interesting connections with the Landau-Ginzb urg and double sine-Gordon models are also established.