A new type of atomic clock may reveal a new physics

MIT scientists have devised a new type of atomic clock that can answer some soft-minded questions, such as the potential impact of gravity on the movement of time and whether time itself change as the universe ages.

This new atomic clock measures atoms that were largely entangled. And these atoms are connected in a way that is impossible according to the laws of classical physics, which allows scientists to measure the vibration of atoms more accurately.

Atomic clocks use lasers to measure the vibration of atoms, which oscillate at a constant frequency, as many microscopic meteorites move in synchronization. The best atomic clocks in the world hold time so accurately that they would be off for only about half a second today if they had run from the beginning of the universe.

The new setup can achieve the same error four times faster than clocks without engaging.

Lead author Edwin Pedrozo-Peñafiel, a postdoc in MIT’s electronic research lab, said, “Improved optical atomic clocks will have the ability to engage in better precision in one second than state-of-the-art optical clocks.”

“If atoms get involved, their oscillations would fluctuate around a common frequency, with less bias than if they were not involved. Thus the average oscillations that an atomic clock would measure would certainly be higher than the Standard Quantum limit. ”

Nearly 350 atoms of ytterbium are involved in this new atomic clock. The atoms open at the same high frequency as visible light, which means that one atom reacts 100,000 times more frequently in one second than a cesium.

Using conventional techniques, scientists cooled down the atoms and captured them in an optical cavity formed by two mirrors. They then passed a laser through the optical cavity, where it connected between the mirrors, interacting with the atoms thousands of times.

Chi Shu, co-author from MIT, said, “Light is a link between atoms. The first atom that sees this light changes the light slightly, and that light also changes the second and third atoms. Through many cycles, the atoms together get to know each other and begin the same behavior. ”

When scientists performed a similar experiment without inactivation of atoms, they found that the atomic clock with atoms involved reached an accuracy that they wanted four times faster. .

Vladan Vuletic, Lester Wolfe’s Professor of Physics, said, “You can always make the clock more accurate by measuring longer. The question is, how long do you need to reach a certain accuracy. A lot of surprises have to be measured on fast timescales. ”

“If today’s modern atomic clocks could be modified to measure largely involved atoms, they would not only keep better time, but could help determine signals. in the universe as dark matter and gravitational waves, and begin to answer questions of age. ”

“As the universe ages, does the speed of light change? Does the cost of the electron change? That is what you can confirm with more precise atomic clocks. “

Magazine Information:
  1. Pedrozo-Peñafiel, E., Colombo, S., Shu, C. et al. Engaging in atomic-clock optical-transition. Nature 588, 414–418 (2020). DOI: 10.1038 / s41586-020-3006-1