Scale-Invariant Gravity: Geometrodynamics

TL;DR

This paper introduces a scale-invariant conformal gravity theory that extends geometrodynamics, removing the volume degree of freedom, and demonstrates its potential to match solar system observations while differing in cosmology and quantization.

Contribution

It develops a novel conformal gravity framework based on best matching, eliminating the volume degree of freedom and closely aligning with geometrodynamics of GR.

Findings

Successfully couples to scalars and gauge fields

Preserves shape degrees of freedom while removing volume dynamics

Potential to match solar system observations

Abstract

We present a scale-invariant theory, conformal gravity, which closely resembles the geometrodynamical formulation of general relativity (GR). While previous attempts to create scale-invariant theories of gravity have been based on Weyl's idea of a compensating field, our direct approach dispenses with this and is built by extension of the method of best matching w.r.t scaling developed in the parallel particle dynamics paper by one of the authors. In spatially-compact GR, there is an infinity of degrees of freedom that describe the shape of 3-space which interact with a single volume degree of freedom. In conformal gravity, the shape degrees of freedom remain, but the volume is no longer a dynamical variable. Further theories and formulations related to GR and conformal gravity are presented. Conformal gravity is successfully coupled to scalars and the gauge fields of nature. It should describe the solar system observations as well as GR does, but its cosmology and quantization will be completely different.