The second It is the most precise unit of measurement we have, compared to the kilogram, the meter or the Kelvin. But how do our watches control time?
Today, time is measured with atomic clocks in different parts of the world, which together tell us what time it is. Using radio waves, atomic clocks They constantly send signals that synchronize with our computers, phones and wrist watches in a world increasingly dependent on precision.
How can the study published by Niels Bohr’s great-grandson improve temporal precision?
To address the need for precision, a new study from the University of Copenhagen may revolutionize the way we measure time. The study, led by Dr. Eliot Bohr, great-grandson of renowned physicist Niels Bohr, proposes an innovative method to measure time with greater precision than the most modern atomic clocks, paving the way for a variety of applications ranging from more accurate GPS to safer space missions.
Atomic clocks are currently the most accurate devices for measuring time, using strontium (Sr) or cesium (Cs) atoms that oscillate at a rate of millions of times per second. However, the accuracy of these watches It is limited by the heating of atoms by lasers used to read oscillations, which contributes to atoms disappearing and decreased overall accuracy.
Eliot Bohr explains that atoms They need to be constantly replaced by new atoms, which causes the clock to lose a little time. To overcome this challenge, they are working on improving current atomic clocks, for example by reusing atoms so that They do not need to be replaced as frequently. Eliot Bohr conducted this research at the Niels Bohr Institute and is currently a researcher at the University of Colorado.
Proposal of an innovative method based on the quantum phenomenon of “super-radiation”
Dr. Bohr and his team then propose an innovative method that uses a quantum phenomenon called “super-radiation” to overcome these limitations in a study published in the scientific journal Nature Communications. “Super-radiation” occurs when a group of atoms become entangled and simultaneously emit a strong light signal. By using mirrors to amplify this light, the oscillations of the atoms can be read with greater precision, without the need to heat them excessively.
This new “super-radiation” technology has the potential to revolutionize various areas that depend on the precision of time. GPS, for example, could become even more precise, allowing for more reliable and efficient navigation. Space travel would also benefit from more accurate atomic clocks, allowing for even safer missions.
In fact, atoms have a temperature of -273ºC, very close to absolute zero, and two mirrors with a field of light, which between them, They can amplify the interaction of atoms.
“Mirrors make atoms react as a cohesive unit and, together, they emit an intense light signal that we can use to read their oscillations with the mirrors and, thus, measure time. All this happens without overheating the atoms and, therefore, we don’t need to replace the atoms, which has the potential to make it a more precise measurement method,” explains Eliot Bohr.
GPS, space missions and volcanic eruptions
According to Eliot Bohr, the most recent result of research can benefit to make the GPS system even more precise. The approximately 30 satellites that constantly orbit the Earth and tell us where we are, They also need the measurement of time by atomic clocks.
“Every time satellites determine the position of your phone or GPS, an atomic clock is used inside the satellite. The accuracy of the atomic clock is so important that if it is just a microsecond off, it could mean an inaccuracy of 100 meters. the surface of the Earth,” explains Eliot Bohr.
In addition, volcanic monitoring also could be improved with more precise atomic clocks, which would allow scientists to detect and predict eruptions earlier.
Setting the clock: NASA’s mission to establish a time zone for the Moon
A “super-radiation” can pave the way for many other applicationsnot yet imagined, that are based on the precise measurement of time.
News reference
Bohr, EA, Kristensen, SL, Hotter, C., Schäffer, SA, Robinson-Tait, J., Thomsen, JW, … & Müller, JH (2024). Collectively enhanced Ramsey readout by cavity sub-to-superradiant transition. Nature Communications, 15(1), 1084. https://doi.org/10.1038/s41467-024-45420-x
