The prospects for extended phase space approach to quantization of gravity

TL;DR

This paper reviews a new approach called quantum geometrodynamics in extended phase space, which treats gauge degrees of freedom as part of the universe affecting quantum gravity, and discusses its potential implications.

Contribution

It introduces and discusses the prospects of a novel approach to quantum gravity that incorporates gauge degrees of freedom as a subsystem influencing physical evolution.

Findings

Gauge conditions influence the form of the wave function and density matrix.

An example shows gauge choice can lead to an almost diagonal density matrix.

Analogy with reference frame transitions in Rindler space is proposed.

Abstract

A brief review of main features of the new approach named ``quantum geometrodynamics in extended phase space'' is given and its possible prospects are discussed. Gauge degrees of freedom are treated as a subsystem of the Universe which affects the evolution of the physical subsystem. Three points can be singled out when the gauge subsystem shows itself as a real constituent of the Universe: a chosen gauge condition determines the form of equation for the physical part of wave function, the form of density matrix and the measure in physical subspace. An example is considered when a physically relevant choice of gauge condition leads to almost diagonal density matrix. The analogy between a transition to another reference frame (another basis in physical subspace) and a transition to accelerating reference frame in Rindler space is suggested.