Status Report and first Light from Cannex: Casimir Force Measurements between flat parallel Plates
Résumé
The Casimir And Non-Newtonian force Experiment(Cannex) was designed to detect Casimir and hypothetical fifth forces between truly parallel plates of cm size, set 10–30 μm apart. With sub-pN sensitivity and large interacting areas, the experiment aims to settle a long-standing question of Casimir physics regarding the role of dissipation at zero frequency in the description of dielectric functions. Active measurement and control of parallelism allows to accurately probe non-standard geometries, such as crossed cylinders or a cylinder opposing a plate. If the designed precision could also be reached in gas at pressures up to 500 mbar,Cannex has been predicted to rule out completely the so-called chameleon model as explanation for dark energy. After a 6-year construction phase, the experiment has reached a first operational prototype state. In the present article, we give an overview of the setup and applied methods, present proofs of principle for key-technologies, and discuss technical hurdles yet to be overcome. Finally, we present first force gradient measurements between parallel plates in the range 6–40 μm.