Discretuum versus Continuum Dark Energy

TL;DR

This paper compares discretuum and continuum models of dark energy, showing their distinct equations of state and discussing how future measurements can test these theoretical predictions.

Contribution

It introduces a continuum dark energy model with large wave function factor Z, demonstrating its stability and unique evolution of the equation of state.

Findings

Discretuum models have constant w=-1.

Continuum models predict a variable w(z).

Future measurements can distinguish these models.

Abstract

The dark energy equation of state for theories with either a discretuum or continuum distribution of vacua is investigated. In the discretuum case the equation of state is constant $w=p/\rho=-1$. The continuum case may be realized by an action with large wave function factor $Z$ for the dark energy modulus and generic potential. This form of the action is quantum mechanically stable and does not lead to measurable long range forces or violations of the equivalence principle. In addition, it has a special property which may be referred to as super-technical naturalness which results in a one-parameter family of predictions for the cosmological evolution of the dark energy equation of state as a function of redshift $w=w(z)$. The discretuum and continuum predictions will be tested by future high precision measurements of the expansion history of the universe. Application of large $Z$-moduli to a predictive theory of $Z$-inflation is also considered.