Quintessence, the Gravitational Constant, and Gravity

TL;DR

This paper explores the concept of quintessence as a dynamic form of dark energy, examining its coupling to gravity and the resulting constraints from solar system experiments on the gravitational constant.

Contribution

It investigates the possibility of a non-minimal coupling between quintessence and curvature, deriving constraints from solar system tests.

Findings

Non-minimal coupling constrained to || c 10^{-2} by solar system experiments.

Quintessence can be consistent with observational data if couplings are sufficiently suppressed.

Scalar field coupling introduces a long-range gravity force compatible with current tests.

Abstract

Dynamical vacuum energy or quintessence, a slowly varying and spatially inhomogeneous component of the energy density with negative pressure, is currently consistent with the observational data. One potential difficulty with the idea of quintessence is that couplings to ordinary matter should be strongly suppressed so as not to lead to observable time variations of the constants of nature. We further explore the possibility of an explicit coupling between the quintessence field and the curvature. Since such a scalar field gives rise to another gravity force of long range ($\simg H^{-1}_0$), the solar system experiments put a constraint on the non-minimal coupling: $|\xi| \siml 10^{-2}$.