  In previous work [1] new bounded coherent states construction, based on a
Keldysh conjecture, was introduced. As was shown in [1] the particular group
structure arising from the model leads to new symmetry transformations for the
coherent states system. As was shown, the emergent new symmetry transformation
is reminiscent of the Bogoliubov ones and was successfully applied to describe
an excitonic system showing that is intrinsically related to the stability and
its general physical behavior. The group theoretical structure of the model
permits to analyze its thermal properties in theoretical frameworks that arise
as a consequence of the definition of the squeezed-coherent states as
transformed vacua under the automorphism group of the commutation relations, as
the thermofield dynamics case given by Umezawa and other similar developments
[5]. On the other hand, the idea of a possible Bose--Einstein condensation
(BEC) of excitons in semiconductors has attracted the attention of both
experimentalists and theoreticians for more than three decades being one of the
main questions what happens with the influence of non zero temperature in the
case that such condensation really exists [2]. In this paper we considered the
theoretical treatment of the excitonic behaviour by mean a new coherent state
construction of bounded states in a quantum field theoretical context.
