Detecting Chameleons through Casimir Force Measurements

TL;DR

Precision Casimir force measurements can potentially detect or constrain strongly coupled chameleon fields, which are not accessible through traditional gravity tests due to shielding effects, with future experiments showing promising prospects.

Contribution

This work investigates the potential of current and future Casimir experiments to detect or constrain strongly coupled chameleon fields, highlighting their advantages over gravity tests.

Findings

Current measurements cannot detect chameleons.

Future experiments could detect or rule out certain chameleon models.

Casimir tests are more effective than gravity tests for strongly coupled chameleons.

Abstract

The best laboratory constraints on strongly coupled chameleon fields come not from tests of gravity per se but from precision measurements of the Casimir force. The chameleonic force between two nearby bodies is more akin to a Casimir-like force than a gravitational one: The chameleon force behaves as an inverse power of the distance of separation between the surfaces of two bodies, just as the Casimir force does. Additionally, experimental tests of gravity often employ a thin metallic sheet to shield electrostatic forces, however this sheet mask any detectable signal due to the presence of a strongly coupled chameleon field. As a result of this shielding, experiments that are designed to specifically test the behaviour of gravity are often unable to place any constraint on chameleon fields with a strong coupling to matter. Casimir force measurements do not employ a physical electrostatic shield and as such are able to put tighter constraints on the properties of chameleons fields with a strong matter coupling than tests of gravity. Motivated by this, we perform a full investigation on the possibility of testing chameleon model with both present and future Casimir experiments. We find that present days measurements are not able to detect the chameleon. However, future experiments have a strong possibility of detecting or rule out a whole class of chameleon models.