Intel develops spin qubits operating at higher temperatures

Intel continues to actively invest in new technologies, and among its latest interests is quantum computing. In the autumn of last year, the first quantum processor based on 17 qubits was presented, and at the previous CES exhibition one of the largest semiconductor manufacturers demonstrated the chip with 49 cubits on board.

Intel, like many others, sees great potential in quantum computers, but technical problems that are on the way to implementing the technology are decreasing yet, unfortunately, not as actively as we would like. For example, the operating temperature of the same chip presented at the exhibition is -273.2 degrees Celsius. Therefore, engineers are now looking for more practical solutions.

Together with scientists from the Dutch Delft Technical University (QuTech), Intel is conducting research with so-called spin qubits. Work on them has been conducted for several years and is considered very promising. Spin qubits are electrons embedded in silicon and located not so much in a spin-down state (binary 0) or spin-up (binary 1), but also in an intermediate state, the so-called superposition. The latter, in turn, is the basis of all the foundations of quantum computers. The plus of spin qubits is that they are not as sensitive to temperature as superconducting qubits, requiring conditions under which they will work effectively, close to absolute zero. In turn, the complexity of cooling systems leaves its imprint on the practicality of the entire system – they do not allow quantum computers to simultaneously use more than a few hundred or thousands of qubits. Talking about systems based on millions of qubits in general seems so far a fiction in such conditions.

Spin qubits can operate at a temperature of 1 kelvin. Superconducting qubits need to be cooled to 20 millikelvin, which is 50 times colder and much more expensive. In addition, cooling in this case occurs not only qubits, but also other components of the quantum computer behind the cooling circuit, which is also not ideal. Spin qubits allow you to transfer the remaining components closer to the qubits, which reduces the complexity of the system.

The second advantage of spin qubits is the possibility of a more dense arrangement in the conditions of the previous volume. Commercial systems will undoubtedly benefit from such scaling.

The third advantage of the spin qubits is their production process, which is pretty close to the classical semiconductor transistors, so many semiconductor companies will be able to adapt this technology much more quickly.

At the next Advancement of Science conference, Intel and QuTech are going to show the first quantum computer based on two spin qubits. As noted by the creators, the system is capable of performing simple algorithms. For the production of qubits, Intel used its 300-mm substrate (as in the image above), completely purified from any isotopes. This is only the first test production, but in the coming months the company promises to increase production volumes and bring it to several substrates per week. Each such substrate can contain several thousand arrays of spin qubits.