Quantum geometrodynamics creates new problems

TL;DR

Quantum geometrodynamics faces new challenges, including the necessity of a reference frame and a self-consistent quantum and thermodynamical description of the Universe, complicating its foundational understanding.

Contribution

The paper highlights the emergence of new problems in quantum geometrodynamics, emphasizing the importance of reference frames and thermodynamics in a quantum cosmological context.

Findings

Quantum description of the Universe requires a reference frame.

Thermodynamical properties depend on the chosen gauge or reference frame.

A self-consistent quantum and thermodynamical framework is necessary.

Abstract

The development of last years in quantum geometrodynamics highlights new problems which were not obvious in its first formulation proposed by Wheeler and DeWitt. At the first stage the main task was to apply known quantization schemes to gravitational field or a certain cosmological model. This way has led to the realization of the fact that a quantum description of the Universe is impossible without implicit or explicit indication to a reference frame presented by some medium, filling the whole Universe, with its own equation of state and thermodynamical properties. Thus the questions arise, should one seek for a "privileged" reference frame or consider all the variety of gauge conditions and appropriate solutions for the wave function? It is worth noting that thermodynamical properties of such a quantum Universe would also depend on a chosen reference frame to some extent. So, we need a self-consistent quantum theoretical and thermodynamical description of the Universe.