What is the Sycamore Quantum Computer

Quantum superiority: five questions about Google's quantum computer

4. How important is the whole thing?

Uninvolved experts consider Google's quantum computer to be an important symbolic milestone. Some compare it to the Wright brothers' maiden flight. The quantum computer expert Frank Wilhelm-Mauch from Saarland University even spoke to Spektrum.de of a “Sputnik moment”. “It's a technological masterpiece,” he says. Andreas Wallraff from ETH Zurich is also impressed: "Google's performance is remarkable."

Quantum physicists are more cautious when it comes to the actual applicability of the technology developed. From the point of view of most specialists, the calculation carried out by Sycamore is a special task that is tailor-made for a quantum computer prototype of this size. "The algorithm is designed in such a way that it is particularly complicated for classic computers," says Wallraff.

In fact, the supremacy experiment only makes sense on a machine with 50 to 60 qubits. In this area, classic computers lose touch with quantum computers when they perform special tasks, but can still just estimate the probability distribution of the random numbers - and in this way verify the results of the quantum computer.

In order for the futuristic machines to take on other tasks that are too complex for supercomputers, however, they have to get significantly better and bigger. One of the main problems are the errors that occur when calculating with qubits. Google was able to reduce the error rate to a few tenths of a percent. But that is still far too little for more demanding tasks.

5. Is the end of privacy looming now?

Depending on the point of view, quantum computers are either a powerful tool that can soon help with optimization problems or complicated quantum simulations in drug development. Or they are a dangerous super weapon. Finally, they can use Shors' algorithm to override the common RSA encryption method, which is still used to encrypt bank transfers and health data, among other things.

Quantum computers are currently not at risk here: In order for Shors' algorithm to crack the RSA encryption, it would have to run on a quantum computer with thousands of error-corrected qubits. When and whether there will be such machines is still completely unclear. Experts assume that it will be decades rather than years - in the best case scenario.

Quantum computers still have to overcome numerous technical hurdles along the way. In the meantime, considerable funds are flowing into quantum computer research, including from the private sector. The hustle and bustle of Google's quantum supremacy should give this trend a boost. However, researchers see the risk that the current enthusiasm could quickly turn into disappointment. If quantum computers fail to meet the expectations raised by investors, the flow of money may dry up again quickly.

You can read a critical comment on Google's quantum computer here.