• Tweeter
  • republish

Sundar Pichai and Daniel Sank in front of a Google quantum computer in Santa Barbara in October 2019. Google / Handout via REUTERS

Google says it has arrived at "quantum supremacy", a pompous expression that indicates that its quantum computer has managed to achieve a calclul that could not do a conventional computer.

Google publishes an article in the columns of Nature , it is not commonplace. But this is the case, on the occasion of the last issue of the prestigious scientific journal. Object: the quantum computer, coveted for decades by scientists for the promises it offers compared to conventional computers.

The American firm announces having passed a major stage in its development. His quantum computer was able to perform a calculation whose result arrived in 3 minutes 20, while it would have taken 10,000 years for the most powerful supercomputers to perform the same operation.

It was necessary to use properties of matter on the quantum scale, that of the infinitely small. Notably what is called superposition: a single particle can be in two places at a time in two different states. Something very well studied, and applied, in lasers for example.

A quantum computer will take advantage of it. For example, in a labyrinth, where a conventional system would test all the paths out, one by one, the quantum computer, for its part, will explore all the paths at the same time, which is much faster. A technological step is thus crossed.

That said, we are still very far from using such a computer. This experiment was only used to show its power, moreover quite relative, because the quantum processors are sensitive. For example, they must be cooled down to -270 ° to work. We are not ready to see them in our offices.

► To read also: Quantum computers, not to put in all hands