Quantum Stability of Chameleon Field Theories

TL;DR

This paper investigates the quantum stability of chameleon scalar fields as dark energy candidates, deriving bounds on their mass to ensure reliable predictions and assessing the potential for experimental tests of these theories.

Contribution

It provides the first detailed estimate of quantum corrections in chameleon models and establishes bounds on their mass for theoretical consistency and experimental viability.

Findings

Quantum corrections impose an upper mass bound of 0.0073 eV for reliable predictions.

Fifth force experiments set a lower mass bound of 0.0042 eV.

Near-future experiments could test all well-controlled classical chameleon theories.

Abstract

Chameleon scalar fields are dark energy candidates which suppress fifth forces in high density regions of the universe by becoming massive. We consider chameleon models as effective field theories and estimate quantum corrections to their potentials. Requiring that quantum corrections be small, so as to allow reliable predictions of fifth forces, leads to an upper bound $m < 0.0073 (\rho / 10 {\rm g\, cm}^{-3})^{1/3}$eV for gravitational strength coupling whereas fifth force experiments place a lower bound of $m>0.0042$\,eV. An improvement of less than a factor of two in the range of fifth force experiments could test all classical chameleon field theories whose quantum corrections are well-controlled and couple to matter with nearly gravitational strength regardless of the specific form of the chameleon potential.