Physicists have made the first step to mass production of quantum computers

© Photo : Schroeder et al. / Nature Communications 2017Алмазная plate with defects, printed Russian and foreign scientistsPhysicists have made the first step to mass production of quantum computers© Photo : Schroeder et al. / Nature Communications 2017

Scientists from MIT and Russia have learned to «print» single-atom defects inside the diamonds, which opens the way for the industrial production of quantum computers on the basis of such «defective» gems said in an article published in the journal Nature Communications.

«Our dream is to create an optical chain that could be transported photonic qubits and would allow us to use a quantum memory when we need it. We are very close to implement our flaws almost perfect,» says Dirk Englund (Dirk Englund) from the Massachusetts Institute of technology (USA).

Qubits represent both memory and compute modules of a quantum computer, which can simultaneously store and a Boolean zero and unit, thanks to the laws of quantum physics. Combine multiple qubits into a single computing system allows you to quickly solve mathematical or physical problems, finding answers to who, with the help of methods of brute force would take time comparable to the lifetime of the Universe.

Mikhail Lukin from Harvard University and a number of physicists from the Russian quantum center, MIT and Harvard have long been working on the creation of qubits on the basis of the so-called «defective» diamonds. Interest in them stems from the fact that qubits based on them fairly easily make and receive, and they are able to work at room temperature. In addition, diamonds can be used as storage of quantum information, a «quantum memory».

The «heart» of the compute module is defect — atom of nitrogen or other element, «wormed» into the crystal lattice of carbon atoms. Scientists have learned to use the spin — direction of rotation — of the electrons of the nitrogen atom and of its nucleus for data processing and qubit storage of information for a very long time.

In recent years, Lukin and his colleagues learned how to connect these qubits to each other and developed a special bus for exchanging data between such «defects», and has also created many other key components critical to the operation of universal and scalable quantum computers.

Factory qubits

The main problem when you create such a «diamond» of computers, how to tell Lukin and his colleagues remained that such defects actually created in a random way. This makes the creation of complex and «bulk» quantum computers based on them extremely difficult, since the position of each qubit must be determined manually. Therefore, scientists for a long time try to find ways of making such defects in specific points on the diamond surface, where they can easily find and «read».

Russian and American physicists were able to solve this problem using a special electronic gun capable of producing a very thin beams of silicon ions. This device allows «aiming» to shoot portions of 20-30 silicon atoms into specific points on the surface of the diamond plate where it should be located qubits, and to determine established whether they are in it for the changing tension of the beam cannon.

Simple irradiation of the diamond plates with this gun, how to tell Lukin and his colleagues, does not lead to the desired results – only 2% of the «holes» in the structure of diamond, who fired an electron gun, turn into defects with the desired properties.

Scientists were able to increase their number to 10 times, further firing of the diamond plate by electron beams, and heating it to a temperature of 1000 degrees after treatment by ions of silicon. High temperature, as explained by physics, make «holes» in the crystal lattice of diamond to migrate from one place to another and connect to silicon atoms, «stuck» in it after firing ion cannon.

This approach, according to Lukin and his colleagues, allows you to create tens of thousands of defects on the surface of a diamond every second, placing them in specific points on the surface of the diamond. This brings us to the creation of «industrial» versions of quantum computers and quantum memory on the basis of such defective diamonds, able to solve the real problem. Scientists believe that a similar technique can be used to «print» and other types of defects, the basis for which will serve Germany the atoms or molecules of molybdenum sulfide, which has more interesting properties.