Is the BKL map an intrinsic feature of the Quantum Mixmaster Universe?

Abstract

We study the quantum Mixmaster dynamics by constructing the corresponding Wheeler-DeWitt equation as a relativistic quantum theory in a pseudo-Riemannian Mini-superspace. The transition amplitude from a Kasner regime to the next one is built via the standard S-matrix of a relativistic scattering, and mediated by a single wall potential. We provide a coherent and convincing representation of the original Misner's idea that quasi-classical states can survive arbitrarily close to the cosmological singularity. By constructing a complete set of states, we demonstrate that the quasi-classical BKL map is preserved by the resulting transition amplitude to a new state when their mean total momentum is high enough (exactly coinciding with Misner's high occupation numbers). This scheme is naturally iterated to the initial singularity without appreciable shape changes. We also clarify the role played by the state localization, and, in particular, we outline that when the incoming state is spread, the possibility of violating the Kasner map is no longer negligible. Thus, Kasner-like wave packets can approach the initial singularity.