British scientists in a recent study measured the frequency difference between two optical atomic clocks based on entangled strontium ions and proved that such measurements will be more accurate than measurements on a single or non-entangled clock.
Atomic clocks, despite their name, bear little resemblance to ordinary timepieces that we wear on our hands or hang in our room. Such a device is primarily aimed at accurate frequency measurement and is used for navigation – in space and on the ground.
Traditional atomic clocks typically rely on excitation of atoms at precise frequencies, while optical clocks use a network of laser beams to capture and isolate individual atoms, allowing scientists to make more reliable measurements.
However, even in the case of optical atomic clocks, noise, especially laser phase fluctuations, can affect accuracy. Much earlier research has focused on minimizing this effect, in particular by repeatedly measuring the frequency. This approach, unfortunately, encounters an error introduced by a single measurement and due to the standard quantum limit, that is, the influence of the measurement on the object itself.
A team of physicists from the University of Oxford, led by Christopher Ballance and David Lucas, had the idea to first confuse the atomic clock and then measure their frequency difference with a laser. Previously, the group had already managed to achieve entanglement of watches at a microscopic distance, but this time the clocks were separated by about two meters, and it turned out that this was not the limit.
The potential for research is enormous: the more accurately humanity can measure the passage of time, the more chances we will have to unravel the greatest mysteries of the universe. For example, if it is possible to create a huge network of atomic clocks and distribute them in space, it may be possible to form a kind of inverted image of the Universe and detect dark matter in real time.
The usefulness of such a network was already considered by researchers in the US and Canada back in 2014, who described in detail in their article the search for dark matter based on synchronized atomic clocks:
“When an extended dark matter object passes through the network, the originally synchronized clocks will become out of sync. It is the divergence in time between the space-separated clocks that will demonstrate a distinct signature “encoding the spatial structure of the defect and the strength of its interaction with atoms.”
If dark matter does exist, the Oxford team’s recent breakthrough could be a major step towards discovering it. However, even in the absence of it, increasing the accuracy of atomic clocks will be useful in many industries.
Source: Thenextweb , Nature
