How cosmic rays harm quantum computers

quantum computer He must be the next great guru of computer technology. They should greatly improve searches and businesses. Problems that the computer cannot currently handle should be resolved as soon as possible.

A quantum processor consists of what is called Quantum bits (qubits) It was built. These qubits can’t just be memorized 1 or 0 It accepts the same as regular bits, but also accepts superposition of the two states – i.e. 0 and 1 at the same time. With a full register of qubits, it becomes possible, quite simply, to perform arithmetic operations with several numbers at the same time.

Cosmic rays vs qubits

One of the biggest challenges in building quantum computers is maintaining the stability of these qubits. For this purpose, superconductors are used, for example, through which qubits are created from pairs of electrons – the so-called Cooper pairs -. Keeping it stable for more than a few 100 microseconds is indeed a colossal effort. Superconductors must be cooled very strongly so that the electron pairs do not decay. Currently it is still -273 degrees, absolute zero.

Studies from MIT (NaturePhysics) and Google (NaturePhysics) have shown that these electron pairs have a big problem: high energy particles, such as cosmic or radioactive radiation. They regularly hit the ground and constantly shot at our bodies. They are also confronted with superconductors. Their energy is sufficient to break electron pairs. MIT was able to determine this as early as 2020, and now Google is analyzing the problem in more depth.

Correcting errors is not enough

“It’s not just the qubits that are suffering, the problem is everywhere. If it’s just localized, there won’t be a problem, it’s just an additional error rate to take into account. That’s why you correct the error. If all my qubits suddenly go bad, you can’t fix them anymore” Gerhard Kirchmeier From the Institute of Quantum Optics and Quantum Information of the Academy of Sciences facing the Quartier du Futur.

In the Google configuration test, swipe with 26 qubits used. Usually the maximum join is on average 4 One of these qubit errors in a certain period of time. As soon as it hit a high-energy particle, that number increased 24. This is a serious problem for quantum computers working with superconductors, says Kirschmeier. Because each time high-energy particles shatter qubits, the process in the quantum computer has to be stopped and restarted.

It’s not only boring, but also defeats the real idea, which is high speed. Moreover, such an event does not occur once a day, but approximately every 10 minutes Before. However, calculations in quantum computers often take several hours.

This is what Google’s quantum computing chip looks like

Look for protection strategies

“It can stop the whole process,” says Kirschmayr. But that certainly doesn’t mean a knockout of technology. “We now need to assess the strategies that will help shield the particles.” So, for example, the data centers of the future huge mountains or deep in the earth to build. This is perhaps one of the simplest solutions.

Other ideas come from Astrophysics, where one would want to make measurements frequently without cosmic radiation constantly interfering with the result. “We can use other materials which dissipate the energy of the particle and therefore do not reduce the coherence time of the qubits”, explains the physicist. Another option would beLocatedwhich captures the broken electron pairs and does not allow them to escape. After that, they won’t affect other qubits and the process can continue.

“It is likely that a combination of these approaches will be used,” says Kirchmeier. The results did not surprise him. We already knew that cosmic rays and radioactive particles had the ability to disrupt superconductors. However, only a Google study was able to show how amazing the effects are. Now, we will have to work on the solutions.