The atoms are trapped in an optical cavity made up of two mirrors. When the “squeezing” laser is inserted into the cavity, the atoms are trapped, and their frequency is measured with another laser, as a platform for more precise atomic clocks. Credit: Courtesy of Researchers
The new atomic clock design, which uses trapped atoms, will help scientists detect dark matter and study the effects of gravity in a timely manner.
Atomic clocks are the most accurate time in the world. These excellent devices use lasers to measure the vibrations of atoms, which swing in sync like many microscopic pendulums, as os silt at a constant frequency. The world’s best atomic clocks keep track of time with such precision that, if they had been running since the beginning of the universe, they would have landed in about half a second today.
However, they may be more specific. If atomic clocks could measure atomic vibrations more accurately, they would be sensitive enough to detect phenomena such as dark matter and Gravitational waves. With better atomic clocks, scientists could even begin to answer some mind-boggling questions, such as what effect gravity has over time and how time can change as the universe ages.
Now a new type of atomic clock designed by MIT Physicists can allow scientists to explore such questions and reveal new physics.
Researchers have reported in the journal today Nature That they have created an atomic clock that measures not the cloud of advanced oscillating atoms, as sophisticated designs now measure, but instead atoms that are trapped in the dimension. Atoms are involved in a way that is impossible according to the laws of classical physics, and it allows scientists to measure the vibrations of atoms more accurately.
The new setup can achieve the same accuracy four times faster, which is four times higher than untrained watches.
“Entanglement-enhanced optical atomic clocks are likely to reach better accuracy in one second than current state-of-the-art optical clocks,” says Edwin Pedrozo-PFL, lead doc at MIT’s research laboratory in electronics.
If sophisticated atomic clocks were adopted to measure trapped atoms like the MIT team setup, their time would improve in this way, throughout the universe, clocks would be less than 100 milliseconds.
Other co-authors of this MIT paper are Simon Colombo, Chi Shu, Albert Adiatulin, Zheng Li, Eric Mendez, Boris Brewerman, Akio Kawasaki, Saisuke Akamatsu, Yanhong Xiao and Lester Wolfe of Physics.
Time limit
Since humans began to track the passage of time, they have used periodic phenomena such as the motion of the sun in the sky. Today, vibrations in atoms are the most stable periodic events that scientists can observe. Also, a cesium Atom The second cesium atom will c at the same frequency.
To keep full time, clocks would ideally track the oscillation of an atom. But on that scale, an atom is so small that it behaves according to the mysterious laws of quantum mechanics: when measured, it behaves like a flipped coin while giving average true probabilities just above many flips. This limit is what physicists call the standard quantum limit.
“When you increase the number of atoms, the average given by all these atoms goes to something that gives a true value,” says Colombo.
This is why today’s atomic clocks are designed to measure gas made up of thousands of similar atoms to get an estimate of its average oscillation. A special atomic clock does this using a system of first lasers to trap the gas of ultra-ooled atoms into a laser-formed trap. Another, very stable laser, with a frequency close to the vibrations of the atoms, is sent to check the atomic oscillation and there is a time tracking.
And yet, the standard quantum limit is still in operation, i.e. between thousands of atoms, regarding their exact individual frequency, there is still some uncertainty. This is exactly the position that Vuletic and his group have shown that quantum trapping can help. In general, quantum antiglaumen describes a nonclassical physical condition in which the atoms of a group behave like a random toss of each other’s coins, however, the molecules of the group show the results of measuring each other.
The team argued that if atoms were trapped, their individual oscillations would tighten around a normal frequency, with fewer deviations than they were not trapped in. The average oscillations that an atomic clock measures, therefore, have accuracy beyond the standard quantum limit.
Trapped watches
In their new atomic clock, Vuletic and his associates are associated with about 350 atoms of ytterbium, which os silt at a frequency as high as visible light, meaning that any single atom vibrates 100,000 times more per second than cesium. If the oscillation of the yttrium can be accurately detected, scientists can use the atom to isolate small intervals of time.
The group used standard techniques to cool the atoms and trap them in an optical cavity formed by two mirrors. They then sent a laser through the optical cavity, where it ping-survived thousands of times in contact between mirrors.
“It’s like a link in a conversation between light atoms,” Shu explains. “The first atom of this light will make a slight change in the light, and that light will also change in the second atom and the third atom, and through many cycles, the atoms will recognize each other en masse and begin to behave similarly.”
In this way, researchers trap atoms in quantities of parameters, and then use another laser similar to current atomic clocks to measure their average frequency. When the team performed the same experiment without trapping the atoms, they found that the atomic clock with trapped atoms reached four times faster than the desired accuracy.
“You can always make the clock more accurate by measuring longer,” says Vuletic. “The question is, how long do you need to reach a certain accuracy? Many events need to be measured on a fast timescale. “
He says that if today’s sophisticated atomic clocks could be adapted to measure the number of trapped atoms, they would not only have a better time, but they could help decipher signals like dark matter and gravitational waves in the universe, and get started. Is. Answer some age-old questions.
“Like the age of the universe, the speed of light also changes? Does the charge of an electron change? Says Vuletic. “This is something you can check with more precise atomic clocks.”
References: Edwin Pedrozo-Pfefil, Simon Colombo, Chi Shu, Albert F. “Fight on Optical Atomic-Clock Transition” by Adiatulin, Zheng Li, Eric Mendez, Boris Brewerman, Akio Kawasaki, Deisuke Akamatsu, Yanhong Xiao and Vladan “16 December 2020, Nature.
DOI: 10.1038 / s41586-020-3006-1
This research was, in part, supported DARPA, National Science Foundation and Office of Naval Research.
