The functioning of a material depends on the interactions between countless numbers of atoms. You can see this as a giant chats where atoms constantly exchange quantum information, researchers at Delft University of Technology in collaboration with RWTH Aachen University and the Jülich Research Center are now able to intercept the conversation between two atoms. They present their findings in science On May 28
Nong Atom doesn’t really talk. But they can meet each other Especially in the case of magnetic atoms “Each atom has small magnetic moments called rotations. These rotations influence each other, just like the compass needle. When you bring them closer together, if you give one of them a thrust, they begin to move. They come together in a very specific way, ”explains Sander Otte, lead researcher. “But according to the laws of quantum mechanics, each rotation can point in different directions simultaneously, creating an superposition, which means that the true transfer of quantum information takes place between the atoms, just like that. talk
To a large extent, this kind of exchange of information between atoms can lead to interesting phenomena. A classic example is superconductivity: the effect in which some materials lose their electrical resistance below the critical temperature. Although it is well understood for the simplest of cases. But no one knows how this effect was achieved in so many complex materials. But of course, quantum magnetic interactions play a key role. For the purpose of trying to explain this phenomenon, scientists are interested in blocking these exchanges. To hear the conversation between atoms
On Otte’s team, they talk about it firsthand: they put two atoms side by side to see what happens. This is made possible by means of a tunneling microscope, a device in which a sharp needle can examine atoms one by one and can even rearrange them. The researchers used the device to place two titanium atoms at a distance greater than one nanometer apart, one millionth of a millimeter apart. At that distance, the atoms are able to detect each other’s rotation. If you do now take one of two spins, the conversation will start by itself.
Usually this twist is done by transmitting a very precise radio signal to the atom. This technique, called spin resonance, is somewhat reminiscent of the operating principle of MRI scanners found in hospitals, has been used with success in quantum bit research. The tool is also available for the Delft team, but it has some downsides. “It’s too slow,” said PhD student Lukas Veldman, lead author of the story. science Publication “You hardly start one spin before the other starts spinning, followed by this way, you won’t be able to check what happens when both spins are placed in opposite directions.”
So the researchers tried the eccentric thing: They quickly reversed the rotation of one of the two atoms with a sudden burst of electric current. To their astonishment, this radical approach resulted in beautiful quantum interactions exactly as the book itself. During a pulse, an electron collides with an atom, causing it to spin. Otte: “But we tend to think that during this process, sensitive quantum information – called coherence – is lost. Each: The history of each electron before the collision is slightly different, and this chaos is Transferred to atomic rotation, breaking coherence. “
The fact that it now appears to be untrue has led to some debate. Obviously, each random electron, regardless of its past, can initiate a coherent superposition: a specific combination of the fundamental quantum state, which is well known and the basis for quantum technology. Almost all forms
“The point is that it depends on the questions you ask,” argues co-author Markus Ternes from RWTH Aachen University and the Jülich Research Center. “The electrons alternate the spin of one atom making it point to the left. You can view this as a measure, subtracting all of the quantum memory. But from the point of view of a combined system composed of two atoms, the situation arises. It is not unusual for the two atoms together.The new state is a perfect superposition, allowing information to be exchanged between them.The main thing that happens is that the two rotations are entangled: a peculiar quantum state that They get more involved. More about each other than it would be classic to be. “
The findings are important for research involving quantum bits. Perhaps in that research you avoid being a little less careful when initiating the quantum state, but for Otte and his team for the most part it is the beginning of a more beautiful experiment. Two atoms But what happens when you use three or ten or a thousand? No one can predict, since computational power is so small for such numbers, maybe one day we will be able to listen to a quantum conversation. That no one has ever heard of before ”
“Independent consistent evolution of atomic pair spin systems initiated by electron scattering” science (2021) .sciencemag.org/cgi/ doi… 1126 / science.abg8223
Offered by Delft University of Technology
Reference: Scientists hear a conversation of two atoms (2021, May 27) .Retrieved May 28, 2021 from https://phys.org/news/2021-05-scientists-atoms-chatting.html.
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