The study compared the aluminum-ion clock and ytterbium lattice clock, located in different laboratories at NIST Boulder, with the strontium lattice clock located 1.5 kilometers away at JILA, a joint institute of NIST and the University of Colorado Boulder. The new measurements were challenging because the three types of atoms involved “tick” at vastly different frequencies, because all the many network components had to operate with extreme accuracy, and because the wireless link required cutting-edge laser technology and design. “These comparisons are really defining the state of the art for both fiber-based and free-space measurements - they are all close to 10 times more accurate than any clock comparisons using different atoms performed so far,” NIST physicist David Hume said. These atomic clock comparisons place the scientific community one step closer to meeting the guidelines for redefinition of the second. And now, researchers are figuring out how to harness that precision to do science and explore the universe.In a significant advance toward the future redefinition of the international unit of time, the second, a research team led by the National Institute of Standards and Technology (NIST) has compared three of the world’s leading atomic clocks with record accuracy over both air and optical fiber links.ĭescribed in the March 25 issue of Nature, the NIST-led work is the first to compare three clocks based on different atoms, and the first to link the most advanced atomic clocks in different locations over the air. The most precise clock in the world would have to tick 33 billion years before losing or gaining a second. By doing this, he will test Einstein's equivalence principle from general relativity, which says that gravity is indistinguishable from non-gravitational acceleration. Kolkowitz wants to build a clock containing two optical lattices, and allow one optical lattice to fall while accelerating the other horizontally at the same rate. Optical lattice clocks use atoms, lined up by lasers in an orderly grid, as a frequency reference. For example, Shimon Kolkowitz of University of Wisconsin-Madison is developing a gravity experiment with a type of atomic clock called an optical lattice clock. Researchers also think they can discover new physics by playing around with the internal hardware of the clocks, whose precise engineering also allows physicists to run experiments not directly related to timekeeping. To meet the size and weight constraints of spacecraft, Warren is developing compact atomic clocks. These clocks would help the spacecraft orient themselves and navigate autonomously, for example. Researchers want to put more atomic clocks on satellites and space missions, Zachary Warren of the Aerospace Corporation said. In 2019, NASA engineers launched an atomic clock in orbit. Better synchronization via this optical fiber could allow for even higher-resolution imaging.Īnother avenue of research is launching atomic clocks in space. ![]() Astronomers used VLBI to capture the first image of a black hole earlier this year, for example. This synchronization could result in improvements in an astronomical imaging known as Very Long Baseline Interferometry (VLBI), a method that involves multiple observatories working together to image an object otherwise impossible to resolve with a single telescope. Mario Siciliani de Cumis of the Italian Space Agency described the construction of a 1800-kilometer fiber optic network in Italy synchronized to one time standard that could potentially be used for geodesy. To increase measurement accuracy, some researchers have started to synchronize facilities to a single precise time standard. ![]() ![]() ![]() Some researchers think that this capability could help them more accurately monitor the change in sea level. Because the presence of gravity affects the rate of time passing, clocks closer to sea level actually tick slower than one on Mount Everest-which means that physicists can use these clocks to monitor the shape of our planet, a scientific field known as geodesy. Precise clocks have far-ranging applications well beyond one's social calendar. In multiple sessions at 2020 SPIE Photonics West on Saturday and Sunday, researchers presented about the latest developments in timekeeping and its applications for physics, astronomy, and geoscience. These record-setting clocks are known as atomic clocks, and they tick according to cycles of extremely stable laser light, whose frequency is set to a quantum mechanical property of an atom, as opposed to a pendulum. Humans can measure time more accurately than any other quantity in the universe.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |