Researchers have developed a quantum analogue of the Sagnac interferometer, a special measuring device used to measure the rotation speed of the Earth and man-made objects.
For the first time, Austrian physicists have measured the Earth's rotation speed with fairly high precision while observing how the planet's motion around its axis affects the properties of entangled light particles moving inside a quantum interferometer. This came in a statement published by the press service of the University of Vienna.
Yu Haotson, a researcher at the University of Vienna, said: Our experiments were a big step forward in measuring the speed of the Earth's rotation around its axis. It has been almost a century since physicists first began using ordinary light to study the motion of the planet around its axis. "We were able to achieve the sensitivity required to make such measurements using entangled amounts of light."
Yu Haotson and his colleagues developed a quantum analogue of the Sagnac interferometer, a special scientific instrument used to measure the rotation speed of the Earth and man-made objects. It consists of a group of light sources and several mirrors that make the light travel clockwise and counterclockwise within a closed loop. The rotation of the object to be studied forces the light rays to “interfere” with each other in a special way, allowing the speed of its rotation to be determined.
The Austrian physicists hypothesized that the accuracy of the "Sagnac" interferometer would increase significantly if it did not use ordinary lasers, but rather used single photon sources capable of producing pairs of more "entangled" light particles. However, the properties of these quantities must be chosen in such a way that measurements of their properties exceed the limitations on measurement accuracy imposed by Heisenberg's uncertainty principle.
Guided by this idea, the scientists assembled a prototype of the SANIAC quantum interferometer, a source of connected entangled photons connected to two kilometer-long pieces of optical fiber wound on an aluminum frame. These parts are connected to each other by a special switch that allows scientists to make the light particles in each ring go in the same direction or in opposite directions.
This switch allowed physicists to neutralize the effect of the Earth's rotation on the operation of the interferometer and measure the planet's speed around its axis to 452 meters per second with a fairly low error of about 30 m/s, relying only on the quantum properties of the photons. Scientists hope that subsequent developments in the operation of quantum interferometers will increase the accuracy of measurements exponentially, and will make it possible to use these tools to observe quantum objects in curved space-time.