F. Bagarello and G. L. Sewell
New structures in the theory of the laser model: microscopic 
dynamics and a non-equilibrium entropy principle
(58K, TeX)

ABSTRACT.  In a recent article, Alli and Sewell formulated a new version of the 
Dicke-Hepp-Lieb laser model in terms of quantum dynamical semigroups, 
and thereby extended the macroscopic picture of the model. In the 
present article, we complement that picture with a corresponding 
microscopic one, which carries the following new results. (a) The 
local microscopic dynamics of the model is piloted by the classical, 
macroscopic field, generated by the collective action of its components; 
(b) the global state of the system carries no correlations between its 
constituent atoms after transient effects have died out; and (c) in the 
latter situation, the state of the system at any time $t$ maximises 
its entropy density, subject to the constraints imposed by the 
instantaneous values of its macroscopic variables.