On the Effective Equation of State of Dark Energy

TL;DR

This paper explores how the effective equation of state of dark energy relates to the ultraviolet cutoff in quantum field theory, suggesting measurements of dark energy can probe fundamental physics.

Contribution

It establishes a relation between dark energy's equation of state and the ultraviolet cutoff, showing vacuum energy can mimic dark energy with w close to -1.

Findings

Effective equation of state can differ from -1 without ruling out vacuum energy.

Infrared measurements of dark energy can probe ultraviolet cutoff scales.

Toy model yields w ≈ -0.96 for Planck-scale cutoff.

Abstract

In an effective field theory model with an ultraviolet momentum cutoff, there is a relation between the effective equation of state of dark energy and the ultraviolet cutoff scale. It implies that a measure of the equation of state of dark energy different from minus one, does not rule out vacuum energy as dark energy. It also indicates an interesting possibility that precise measurements of the infrared properties of dark energy can be used to probe the ultraviolet cutoff scale of effective quantum field theory coupled to gravity. In a toy model with a vacuum energy dominated universe with a Planck scale cutoff, the dark energy effective equation of state is -0.96.