Key points are not available for this paper at this time.
The self-adjointness of an evolution operator _ corresponding to the model of the flat FRW universe with massless scalar field and cosmological constant quantized in the framework of loop quantum cosmology is studied in the case >0. It is shown that, for <₂10. 3₋^-2, the operator admits many self-adjoint extensions, each of the purely discrete spectrum. On the other hand for ₂ the operator is essentially self-adjoint, however the physical Hilbert space of the model does not contain any physically interesting states.
Kamiński et al. (Fri,) studied this question.