Dual atomic clocks in the U.S. will help to find dark matter

Двойные атомные часы из США помогут найти темную материю

Double atomic clock, developed in the US, has accelerated the work of these devices measure the time 10 times, that will allow you to use them to search for traces of the mysterious dark matter flying through Earth, according to a paper published in the journal Nature Photonics.

“We have removed the main source of noise in our hours, which made their signal clearer. This means that now we can achieve the best accuracy of work hours is about 1.5 errors per trillion “ticks” only a few thousand seconds. The accuracy of these hours is not much faster than our previous record, but they are on this level 10 times faster,” said Andrew Ludlow (Andrew Ludlow) from the National Institute of standards and technology (NIST) in boulder.

How they work similar hours? They ions are in special electromagnetic “trap”, are cooled to temperatures close to absolute zero. Scientists “shoot” these ions from the laser, causing them to waver between excited and normal energy States. Similar designs allow you to achieve incredible accuracy of time measurement — a modern atomic clock start to lag or rush for a second only after billions of years.

Three years ago a group of physicists under the leadership of Ludlow were able to improve this figure ten times, creating an atomic clock based on ytterbium atoms. As a rule, as the basis for an atomic clock uses atoms of alkali metals such as cesium, however, Ludlow and his colleagues have managed to replace them with ytterbium, creating a special optical “cage” of laser beams.

Each such cage-trap contains tens of thousands of atoms under resonant laser pulses with a frequency of 518 trillion times per second. The nature of these oscillations does not depend on environmental conditions, which allows their use for timing. According to scientists, the use of ytterbium improved the accuracy 10 times in comparison with the most accurate cesium atomic clock, and has significantly reduced the time of their start.

Now Ludlow and his team managed to improve the work such hours, eliminating their main drawback – small fluctuations in the frequency of the laser pulses, the so-called “noise dick” that come up when working even the most finely tuned lasers.

Experimenting with atomic clock 2013, Ludlow found that this type of interference can be almost completely suppressed, if you connect together two similar device, in which the atoms oscillate at different frequencies.

Alternately “firing” them using the same laser and comparing the response time of the atoms on the pulses of light, scientists from NIST have learned to quickly “catch” errors in the work hours that allowed them dozens of times to accelerate atomic clocks at the highest possible level of accuracy.

Deal with this interference, scientists have now encountered a new problem – increasing accuracy of hours now prevent the atoms themselves, whose quantum properties are not given accurately measure their position and distance, which are the emitted photons.

Nevertheless, the achieved measurement accuracy of 1.5 parts in a million trillion “ticks” – and speed hours should be enough to solve one of the most ambitious goals of modern physics – the search and disclosure of dark matter, whose share accounts for 75% of the mass of the Universe.

How the watch can help in the search for dark matter? In 2014, the Russian physicists Andrei Derevianko and Maxim Pospelov showed that the passage of large lumps of dark matter through the Earth should slow down over time in those parts of the planet, through which they flew. Atomic clock having a sufficiently high accuracy and speed, will be able to detect this anomaly, and thus confirm that dark matter exists. In addition, the high accuracy clock will help physicists to Refine the values of many fundamental constants, and to redefine the kilogram and the meter.