Detection of the Rotation of the Earth with a Superfluid Gyrometer

The effect of the rotation of the Earth, Ω_, on a superfluid resonator equipped with a 4.0cm² rotation pickup loop and with a microaperture is reported. The velocity circulation induced in the loop by the rotation is detected by phase-slippage techniques. The magnitude of Ω_ is measured to better than 1%, and the north direction to ±0.5^∘ for a 10 h observation time. This experiment is the superfluid counterpart of interferometric measurements based on the Sagnac effect.