The effect of gravity-induced time dilation has been measured on the smallest scale ever. This has been observed on a scale of 30 centimeters using stars, supermassive black holes, and atomic clocks, as predicted by Einstein’s theory of general relativity (12 inches). The new research, which was published in the journal Nature, lowered the previous record by one millimeter. A phenomenon known as gravitational redshift was used to measure the time dilation. This is where the relativity effect comes into play.
When a photon – a light particle – escapes a gravitational well (in this case, our planet), the photon’s wavelength is stretched by the gravity of a huge object, moving towards the electromagnetic spectrum’s end scale. This observation, as we noted when the research was published on the ArXiv a few months ago, not only highlights how revolutionary the new optical atomic clocks are, but also brings us closer to being able to measure gravitational effects in the quantum realm. It would take a clock that was 50 times more exact.
In a statement, senior author professor Jun Ye of the Joint Institute for Laboratory Astrophysics and the National Institute of Standards and Technology said, “The most important and exciting result is that we can potentially connect quantum physics with gravity, for example, probing complex physics when particles are distributed at different locations in the curved space-time.” “It also shows that there are no technical barriers to creating clocks 50 times more exact than they are now, which is excellent news.”
The experiment’s clock set a new record for quantum coherence, or how the energy numbers ticked between energy levels. For a total of 37 seconds, they sang in unison. The redshift was determined by examining two separate sections of an atom cloud made up of 100,000 strontium atoms at temperatures near absolute zero. They were able to discover a change in timekeeping by observing how these atom cloud regions behaved. The measured gravitational redshift over the atom cloud was extremely small, in the order of 0.0000000000000000001 (one part in 10 billion billions), but it was entirely compatible with theory predictions.
“This is a whole new ballgame,” Ye explained, “a whole new realm where quantum physics in curved space-time may be probed.” “We will be able to observe the atoms’ entire matter waves across the curvature of space-time if we can measure the redshift 10 times better than this.” “Being able to quantify time differences on such a small scale could lead to discoveries like gravity disrupting quantum coherence, which could explain why our macroscale world is classical.”
These ultra-precise clocks can be used for more than merely pushing the boundaries of known particle physics. They might be used to examine dark matter, a mysterious, invisible substance that exceeds ordinary matter five to one. They could also aid in the mapping of the Earth’s innards by detecting gravity with great accuracy. When it was revealed that Professor Ye had won the 2022 Breakthrough Prize in Fundamental Physics, he told IFLScience, “There will be extremely intriguing discoveries waiting for us if we get to the times that are sensitive to the very small space-time curvature.”
