Quantum entanglement to measure Earth’s rotation

Scientists have carried out a pioneering experiment in which they have measured the effect of the Earth’s rotation on quantumly entangled photons. The experiment represents a significant achievement that pushes the limits of rotation sensitivity in quantum entanglement-based sensors, potentially laying the foundation for new avenues of research at the intersection of quantum mechanics and general relativity.

The experiment was carried out by a team including, among others, Raffaele Silvestri and Philip Walther, both from the University of Vienna in Austria.

Optical Sagnac interferometers are the devices most sensitive to rotations. Their unparalleled precision has positioned them as the definitive tool for measuring rotation speeds, with the only limitation that they cannot go beyond classical physics.

Interferometers employing quantum entanglement have the potential to overcome that limitation. However, the promised quantum leap in sensitivity has been hampered by the extremely delicate nature of quantum entanglement. This is where the new experiment makes a difference.

Silvestri, Walther and their colleagues built a giant fiber-optic Sagnac interferometer and kept the “noise” low and stable for several hours. This made it possible to detect enough pairs of high-quality, quantum-entangled photons to exceed the precision of previous rotation measurements by a thousand times.

The experiment has successfully captured the effect of the Earth’s rotation on a state of maximum quantum entanglement between two photons.

Artistic recreation of the experiment. (Image: Marco Di Vita. CC BY)

Furthermore, the results confirm the interaction of rotating reference frames with quantum entanglement, as described in Einstein’s theory of relativity and quantum mechanics.

Silvestri, Walther and their colleagues present the technical details of their experiment in the academic journal Science Advances, under the title “Experimental Observation of Earth’s Rotation with Quantum Entanglement.” (Fountain: NCYT by Amazings)