In one minute

Roberto Onofrio reviews the search for deviations from Newtonian gravity at micrometre distances, where several theories allow new forces of gravitational strength that could signal unification. In that range the Casimir force is the main background. He reviews micrometre-range Casimir measurements, the limits they place on non-Newtonian gravity and the main sources of false signals. He proposes expressing every Casimir measurement, independent of geometry, as a determination of the constant ħc, which can be checked against its precise microscopic value. Mastering the finite temperature correction, with blind tests, is the key step before future experiments can discover such forces or push their window into theoretically unnatural regions.

Casimir forces and non-Newtonian gravitation