Cosmology and short-distance gravity

TL;DR

This paper explores the implications of interpreting dark energy as vacuum energy, suggesting that effective gravity might only be valid up to TeV scales, which conflicts with observations of primordial gravitational waves.

Contribution

It proposes a link between vacuum energy scale and the cutoff of effective gravity, challenging the conventional cosmological model at high energies.

Findings

Effective gravity may be limited to TeV energy scale.

Primordial gravitational wave background constrains vacuum energy models.

Standard cosmology may need revision at high energies.

Abstract

If the observed dark-energy density $\rho_\Lambda$ is interpreted as the net contribution of the energy density of the vacuum, $\rho_\Lambda \equiv \rho_V \sim M_V^4$, and the corresponding vacuum length scale $\lambda_V = M_V^{-1}$ as the cutoff scale controlling the low-energy, effective field-theory limit of gravity, it follows that the conventional cosmological scenario based on the effective gravitational equations may be valid only up to the Tev energy scale. Such a possibility would be strongly disfavored by the existence of a relic background of primordial gravitational radiation of intensity compatible with present (or near future) experimental sensitivities.