Scientists managed to stop the light for one minute

Original author: Sebastian Anthony
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Researchers from the University of Darmstadt (Germany) managed to stop the flow of light for one minute. Light, as the fastest matter known in the universe (speed 300,000 km / s) was stopped inside the crystal. Thus, it is possible to create the so-called light memory , when the information carried by the light is accumulated by the crystal. In addition to the fact that such a study itself excites the imagination, it, with very great success, can become the background for creating long-range quantum networks, and maybe this study will give tips on how to make the speed of light greater than the value limited by the universe .



If we turn to history, then in 1999, scientists managed to reduce the speed of light to 17 m / s., And then, two years later, the same group of researchers completely stopped the light, but only for a few fractions of a second. Earlier this year, researchers at the Georgia Institute of Technology (USA) managed to stop the light by 16 seconds, and now, scientists from Darmstadt have increased this threshold by a minute.

To stop the light, scientists used the so-called Electromagnetically Induced Transparency (EIT) technique.. They used a cryogenically cooled completely opaque crystal of an alloy of yttrium silicate and praseodymium. The controlled laser beam is directed into the crystal, and thereby creates a complex reaction at the quantum level, making the crystal completely transparent. The second light source (data / image source) is then sent to a fully transparent crystal. Then, the controlled laser turns off, returning to the crystal a state of complete opacity. This action not only allows you to enclose the light that transfers data into the crystal trap, but also eliminate its reflection due to opacity. Thus, the light is stopped.



Due to the lack of freedom of movement, the energy of photons is collected by the atoms of the crystal and the data transferred by light is converted into atomic spins(not to be confused with the human back). To release light from the crystal, a controlled laser is switched on again, making the crystal transparent again, and atomic spins are released by photons. These atomic spins can maintain coherence (data integrity) for a minute, after which a ray of light disappears. In essence, the creation of such conditions allows for the storage and receipt of data from light memory.

In the image above, you can see how scientists have successfully saved a simple image (three horizontal lines) in a crystal for 60 seconds. It seems possible to store data in a crystal for a longer period of time if other chemical elements are used, such as europium doped with yttrium silicate and using specially created magnetic fields.

The light memory providing quantum coherence (such as polarization and quantum entanglement) is a vital moment for creating long-range quantum networks. As with conventional electronic routers, quantum routers must be able to store incoming packets and then forward them - something that allows for such a discovery. Moreover, there are several barriers to overcome, before you can switch to quantum Internet, for example, you need to find a way to coherently store light, accompanied by so little noise that single photons could be safely stored / received and all this needs to be done in room temperature conditions. Cryogenics, is quite applicable in the conditions of some data center,

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