Scientists from the University of Oxford recently published the results of a stunning experiment in which they intertwined two atomic clocks at a record distance of two meters.
In front: Atomic clocks have been popular since the 1950s. They are used in countless applications ranging from managing fairness in the stock market to allowing spaceships to navigate at extreme speeds.
The Oxford team’s experiment involved a relatively new wrinkle in the formula called an optical atomic clock.
While traditional atomic clocks typically rely on activating atoms at precise frequencies (read: they zap microwaves), the optical variant uses a grid of laser beams to capture and isolate individual atoms.
With the optical technique, the researchers are essentially measuring light-emitting atomic transitions as opposed to those emitting microwaves. This allows scientists to make more robust measurements.
What makes the Oxford team’s experiment exciting is that they tangled up two separate atomic clocks about two meters apart.
According to the teams research paper:
Measurements on independent systems are limited by the standard quantum limit; measurements on entangled systems can exceed the standard quantum limit to achieve the ultimate precision allowed by quantum theory – the Heisenberg limit.
Background: Scientists have managed to entangle atomic clocks on a microscopic level, but to our knowledge this is the greatest distance two optical atomic clocks have ever entangled.
In essence, the Oxford team has managed to create a network of two nodes of atomic clocks at a very useful distance – a network that can theoretically be enlarged.
Moreover, hypothetically, there is no limit to the number or type of nodes that can be added to a network of entangled atomic clocks.
Scientists currently use a math-based consensus between dozens or hundreds of different atomic clocks to arrive at the most accurate measurements possible. But entangled clocks are theoretically capable of much greater accuracy.
Quick take: The potential implications for this research are enormous. The more accurately we can measure the passage of time, the closer we come to unraveling some of the universe’s greatest mysteries.
If we can develop a huge network of atomic clocks spreading out in space, it’s possible we could form a kind of inverted image of the universe that reveals dark matter in real time.
American and Canadian researchers predicted the usefulness of such a network in a paper from 2014 detail of a dark matter detector based on synchronized atomic clocks:
During the encounter with an expanded dark matter object, as it races through the network, synchronized clocks will be desynchronized initially. Time differences between spatially separated clocks are expected to show a clear signature, encoding the spatial structure of the defect and the interaction strength with atoms.
In other words, if dark matter exists, the Oxford team’s recent breakthrough may be our best clue yet. And, best of all, there’s not much downside to pursuing this research. Even if the dark matter theory doesn’t work, there are countless practical applications for more accurate atomic clocks.
H/t: Mike McRae, Science Alert