Metastable states of an Ising-like thermally bistable system

The lifetimes of the metastable states are investigated in an Ising-like mo del associated with thermally bistable systems. A discrete mesoscopic Marko vian dynamic is established using an optimized version of the previously pr esented Monte Carlo entropic sampling method. This is well suited to an ext ensive study of the role of the physical parameters: temperature, interacti on parameter, electronic energy gap. By combining a discrete Markovian meso scopic dynamic and the absorbing Markov chain technique, we obtain an analy tical access to the average lifetime of the metastable state. One-variable and two-variable approximations for the original microscopic master equatio n are presented and discussed. A typical difference in the thermal dependen ce of the lifetime of the low- and the high-temperature metastable states i s found, and explained as a consequence of the temperature-dependent field associated with the Ising-like model. The validity, the advantages, and the limits of the method are discussed, as well as the possible consequences o n the behavior of spin transition systems. A prospective for a possible phe nomenological finite-size scaling is presented. [S1063-651X(99)16010-0].