LONDON - Researchers studying ultra-cold atoms have made a clock that takes 300 million years to lose just one second.

The atomic clock, which is twice as accurate as any similar device made previously, may believably turn out to be useful for measuring distances to far away galaxies, or for tracking tiny movements in the Earth’s crust that may give a warning of earthquakes.

Its makers have revealed that the clock consists of gas atoms trapped in a magnetic field and cooled almost to absolute zero, or minus 273 Celsius, the coldest temperature permitted by the laws of physics.

According to them, focused beams of laser light cause the atoms to switch between energy states as electrons swing from one orbit to another, and such oscillations make the clock “tick”.

The scientists were not very impressed when they previously hit an accuracy barrier of one second lost in 150 million years.

They said that that seemed to be because the atoms making up the clock, which belonged to a non-interacting class called “fermions”, were colliding - something they were not supposed to do under the laws of quantum physics.

They found that the laser light used to operate the clock was itself interfering with the atoms and causing the problem.

The team said that the solution for the problem would be to “re-tune” the light frequency in a certain way that brought the atoms under control.

Their efforts led to the present increase of accuracy to one second lost per 300 million years.

“It was a fascinating journey into the world of quantum mechanics. We found out that not all fermions were the same. At the very low temperatures the fermions begin to ’see’ each other and interact and then the atomic clock begins to go awry,” the Daily Express quoted Professor Jan Thomsen, a nuclear physicist from the Niels Bohr Institute at the University of Copenhagen in Denmark, who worked on the clock, as saying.

The scientists are continuing to search for even more accuracy.

“We dream of getting an atomic clock with perfect precision,” said Prof Thomsen.

A research paper on this work has been published in the journal Science. (ANI)