Quantum empty Bianchi I spacetime with internal time

Understand

We discuss the question of time in a Bianchi I quantum cosmology in the framework of singularity avoidance.

• We show that time parameters fall into two distinct classes, that are such that the time development of the wave function either always leads to the appearance of a singularity (fast-gauge time) or that always prevents it from occurring (slow-gauge time).
• Furthermore, we find that, in the latter case, there exists an asymptotic regime, independent of the clock choice.
• This may point to a possible solution of the clock issue in quantum cosmology if there exists a suitable class of clocks all yielding identical relevant physical consequences.