Scientists from Novosibirsk managed to capture and photograph a single atom

A scientific group from the Institute of Semiconductor Physics. A. IN. Rzhanov SB RAS Novosibirsk State University and the Technical University succeeded not only in fixing a separate rubidium atom in the so-called optical tweezers.

But also "catch" an atom in the created trap using a video camera with a long-focus lens.

Why such research is needed

This achievement is very important in the sense that single atoms can act as qubits - the main cells for recording and transmitting information flows in quantum computers.

So, fixing an atom in an optical tweezers (another name is a dipole trap) is one of the most important elements in the formation of an array of qubits and further implementation of quantum transformations.

It is quite logical that the array will contain a huge number of atoms held in this way, which means that it is necessary not only to hold, but also to correctly register the atoms.

How did you manage to photograph an atom

So, the scientists faced a very difficult task. After all, it was necessary to initially cool the atoms (in such a cooled form, the electronic states can persist up to a couple of seconds, which is more than enough for quantum computers) and thus "slow down" them.

And also a separate atom must still be fixed in a trap, which is nothing more than a special laser beam with a focusing of several microns.

And the most difficult thing was still to capture the atom. After all, it is necessary to check the registration of infrared photons scattered by an atom in the shortest possible time. And according to the experimental conditions, the fixation of atoms should take place in the shortest possible time. Only in this case it will be possible to use them as qubits.

Western colleagues use highly efficient EMCCD cameras - electron multiplier video cameras for fixation. But since 2015, they have not been supplied to Russia, and their price is about 5 million rubles.

Our specialists used a much cheaper analogue of the previous generation sCMOS - cameras and achieved amazing results, namely:

It turned out to fix the atom with the minimum possible exposure time - 50 milliseconds. This time is comparable to the work of foreign colleagues who use ultra-modern and expensive cameras.

What was the main problem, how was it solved

As one of the authors of the study, I. Beterov, the main problem was that a single atom emits an extremely weak glow, and therefore all focusing was performed on one pixel of the video camera matrix.

In the course of numerous experiments, it was possible to find out that if you just try to register an atom, then it is hardly distinguishable against the background of noise. To get around this problem, it was decided to turn off the dipole trap for a short time (by 0.000001 s).

For such a short period of time, the atom simply did not have time to leave the trap.

The on-off cycle was repeated on the order of several thousand times, thereby accumulating the signal during the off period of the dipole laser.

This is the first work in the world when the combined use of a long-focus lens and an sCMOS-video camera was successfully carried out, and the result will be of interest to scientists around the world.

Scientists published the results of their research on the pages of the journal "Quantum Electronics".

Physicists from Novosibirsk have plans to learn how to control one-qubit operations with increased accuracy and thus smoothly approach two-qubit operations. Thus, proceed to the "preparation" of the logical elements of the quantum computer.

If you liked the material, then you have a like, comment and subscription. Thanks for attention!