Constraints on Extra Dimensions from Cosmological and Terrestrial Measurements

TL;DR

This paper discusses how measurements from cosmology and laboratory experiments constrain the size and properties of hypothetical extra compact dimensions, suggesting they are either nonexistent or tightly bounded.

Contribution

It provides combined cosmological and terrestrial constraints on the size of extra dimensions based on vacuum energy and deviations from Newton's law.

Findings

Cosmological data sets a lower bound on extra dimension size.

Laboratory tests impose upper limits on deviations from Newtonian gravity.

Allowed parameter space for extra dimensions is extremely narrow.

Abstract

If quantum fields exist in extra compact dimensions, they will give rise to a quantum vacuum or Casimir energy. That vacuum energy will manifest itself as a cosmological constant. The fact that supernova and cosmic microwave background data indicate that the cosmological constant is of the same order as the critical mass density to close the universe supplies a lower bound on the size of the extra dimensions. Recent laboratory constraints on deviations from Newton's law place an upper limit. The allowed region is so small as to suggest that either extra compact dimensions do not exist, or their properties are about to be tightly constrained by experimental data.