Saturday , April 17 2021

These atomic clocks are sensitive enough to measure the distortion of space-time – Science News



These clocks are so delicate that they can only lose half a second if the universe can survive. 14 billion years.

key points

Key points:

  • The most accurate clocks in the world are atomic clocks that use lasers and electrons to adjust the "mark" rate.
  • New ultra-precision atomic clocks based on Ytterbium have record-breaking stability and synchronization
  • By measuring space-time distortion, atomic clocks like these can help discover the interior of the world and identify dark matter.

However, they will not be used to prevent the timely operation of trains. Today's outlined in Nature means precision precision can measure how space-time strikes under gravity forces.

Finally, astrophysicists could write their help to identify the mysterious dark matter.

More, the clocks could tell us what was going on in the world by precisely mapping our planet's blows and clumps – if the clocks were shrunk, I mean.

The author of the work co-author, Will McGrew, a doctoral student at the National Institute of Standards and Technology in the United States, said that the “marking esi of clocks is generated by the emitted radiation oscillations when electrons in the ytterbium atoms are stimulated by lasers.

They're almost 500 trillion times per second, almost perfect together.

"With such incredible accuracy, the time and frequency of measurement provide a truly powerful lens to monitor the natural world," Mr. McGrew said. Said.

Atomic time 101

Measurement time is based on astronomy. For example, the length of a day was determined by a rotation of the Earth on its axis.

However, astronomical phenomena tend to slow down or accelerate.

Today, every millennium more than 1.7 milliseconds, the moon goes through the gravitational tango.

So for astronomical time scheduling and things like that, science requires precision.

And this is where atomic time shines.

Instead of looking at heaven, this time-consuming form enters the waves of radiation evoked by atoms when washed in laser light.

What does atomic clocks do?

What do atomic clocks do?

  • It is defined by the movement of electrons in a cesium-133 atom containing a nucleus containing 55 protons and 78 neutrons surrounded by 55 electrons for a second.
  • As electrons move around the nucleus, they occupy different trajectories or "energy levels".
  • Electrons can "jump" between levels when they absorb or release a certain amount of energy.
  • The energy emitted each time an electron makes a certain jump is always the same and in the form of a microwave.
  • These microwaves have a certain frequency (the number of complete waves completed per second) that can be measured as the "marking" ratio of the atom.
  • Cesium-133 "ticks every 9,192,631,770 times per second"

They come in super futuristic, but atomic clocks have been over 60 years.

The first atomic clock to be used to set the time was made in 1955 in the United Kingdom National Physical Laboratory.

It was true in one second in 300 years.

After 12 years, the cesium atomic clock became the international standard of time, and over time, atomic clocks became much more accurate.

Modern atomic clocks that use strontium or ytterbium instead of cesium loses every 300 million years.

More than time holders

The sensitivity of atomic clocks means that Albert Einstein tested the theory of general relativity, predicting that time was moving faster or slower under the influence of different gravitational forces.

In other words, a clock placed in a satellite orbiting higher "gravity potential" will mark an hour at sea level faster.

And there are already atomic clocks revolving around the Earth on satellites that benefit from this time expansion effect.

We wouldn't have a global positioning system or GPS.

Another use of satellite-mounted atomic clocks is to accurately map the orientation of the Earth in the distribution of size and shape, space and mass, so-called "geodesic".

Satellite geodesy usually involves timing how long the light lasts to make the distance between remote points, such as when a laser glows up to a satellite and how long it takes to retreat to a receiver on Earth.

GPS geodesy is about one centimeter, said Matt King, who used satellite geodesy at the University of Tasmania and did not participate in the study.

But watches that have a higher "tick" rate – ie, higher frequency – wouldn't have to use light at all. Use the relative effects of gravity.

This is what Mr. McGrew and his colleagueswould like to achieve with their atomic clocks.

They used ytterbium instead of cesium. The radiation waves emitted by the Ytterbium atoms shake about five degrees of magnitude faster than those from the cesium atoms.

In the paper, the teams showed that the almost unstable – almost inconceivable loss or gain of the clocks – almost perfectly combined.

Thus, by comparing the locking difference between two ytterbium hours placed on separate continents, one could measure as much as possible the difference in height of the watches to a centimeter.

Professor King said using the precision of ultra-precise atomic clocks would be like having an "inside telescope".

"Let's say there's an earthquake," he said.

”If you can really measure it, you can learn the basics of the viscosity or flow of the interior of the world.“

When the glaciers melt or sink during the pumping of groundwater, the Earth can be monitored by atomic clocks.

By seeing how the soil around a volcano rose and declined even on a lower centimeter scale, Professor King was able to tell the volcanologists that the magma was moving downwards.

"Combine that with seismology and get a real picture of what's going on inside."

Great applications, compact clock

And what prevents atomic clocks from rotating towards volcanic and earthquake risky places all over the world?

Simply, ytterbium clocks are great for moving.

"[The clocks] Mr. McGrew basically deals with a very large lab.

This is because they need a lot of great lasers to work with.

Several lasers cool the ytterbium atoms to a fraction above absolute zero (-273 degrees centigrade) while others keep the cooled atoms in place.

Mr. McGrew and his colleagues are already working on downsizing systems.

Professor King is optimistic that ultra-precise atomic clocks will be as compact as possible in the world in space.

"Computers were used to fill all rooms.

"If we can be 20 years later, it may be earlier, but if [ytterbium clocks] It can be miniaturized and if the sensitivity increases, then there is no shortage of application. "

Strange and wonderful

Atomic clocks below the fragment can be used for experiments involving measuring the smallest distortions in space-time; for example, the incredibly thin tension and crushing caused by a gravitational wave.

Take the dark matter, for example. Astrophysicists know that the dark matter is there and constitutes a quarter of all the mass and energy in the universe.

But the "dark" nature – it does not appear to emit, absorb or emit radiation – it is very difficult to detect.

Mr. McGrew said that a model of dark matter suggests that it can interact with ordinary matter by changing the fundamental constants of nature.

And this is where atomic clocks can help astrophysicists learn a little bit about difficult things.

Mr. McGrew said, "Tell me there's a big dark matter thing passing through a lab that has a ytterbium watch and strontium watch."

"[The dark matter] ytterbium affects one factor, then strontium with another factor.

"By measuring the difference between two hours, you can detect the presence of the dark matter object.

"These are extremely subtle effects, but you can detect them when you can measure up to 18 digits."

And, of course, there are purposes that we haven't dreamed of yet.

Mr. McGrew said, "People who did atomic clocks first didn't know they were building a GPS device." Said.

"I think there's something similar to say about atomic clocks – their most prominent, most important practices are not yet considered."

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