Babak Vakili, Nima Khosravi
In an open Friedmann-Robertson-Walker space (FRW) background, we study the classical and quantum cosmological models in the framework of the recently proposed nonlinear massive gravity theory. Although the constraints which are present in this theory prevent it to admit the flat and closed FRW models as its cosmological solutions, for the open FRW universe, it is not the case. We have shown that either in the absence of the matter or in the present of a perfect fluid, the classical field equations of such a theory adopt physical solutions for the open FRW model, in which the mass term shows itself as a cosmological constant. These classical solutions are consisted of two distinguishable branches, one is a contacting universe which tends to a future singularity with zero size while another is an expanding universe having a past singularity from which it begins its evolution. A classically forbidden region separates these two branches from each other. We then employ the familiar canonical quantization procedure in the given cosmological setting to find the cosmological wave functions. We use the resulting wave function in order to investigate the possibility of the avoidance of classical singularities due to quantum effects. It is shown that the quantum expectation values of the scale factor, although have either contracting or expanding phases like its classical counterparts, but they are not disconnected from each other. Indeed, the classically forbidden region may be replaced by a bouncing period in which the scale factor bounces from the contraction to its expansion eras. By the Bohmian approach of quantum mechanics, we also compute the Bohmian trajectory and the quantum potential related to the system which their analysis shows the direct effects of the mass term on the dynamics of the universe.
View original:
http://arxiv.org/abs/1204.1456
No comments:
Post a Comment