Neutron Limit on the Strongly-Coupled Chameleon Field

Understand

The physical origin of the dark energy that causes the accelerated expansion rate of the universe is one of the major open questions of cosmology.

• One set of theories postulates the existence of a self-interacting scalar field for dark energy coupling to matter.
• In the chameleon dark energy theory, this coupling induces a screening mechanism such that the field amplitude is nonzero in empty space but is greatly suppressed in regions of terrestrial matter density.
• However measurements performed under appropriate vacuum conditions can enable the chameleon field to appear in the apparatus, where it can be subjected to laboratory experiments.