The Google study, which claims to have experienced "quantum supremacy" with a processor capable of computing in three minutes instead of … 10,000 years, is officially released Wednesday in Nature magazine, after escaping by mistake last month.
"This is the sign we were waiting for."welcomed Google CEO Sundar Pichai." It took 13 years to get there. This is the most significant step in the quest for quantum computing, "he continues on his blog.
The study of the digital giant was broadcast briefly in September on NASA's website and unveiled following the Financial Times before being withdrawn.
A team of Google researchers describes how they managed to create a processor called Sycamore that can perform a 200-second calculation where a "classic" supercomputer would have put, according to its references, "about 10,000 years."
"This phenomenal acceleration compared to all known classical algorithms is an experimentation of quantum supremacy."According to the Nature researchers, this calculation, specific to this experiment, is, according to them, a" step on the way "of the highly anticipated universal quantum computer in the computer world, where it is considered a Grail.
Sycamore was able to run a 53-qubit program, the basic foundation of quantum computing.
Unlike conventional computer bits that can be in only two states, 0 or 1, qubits can be in multiple states at the same time. This superposition of states, the basis of quantum physics, creates a "parallelism" that allows multiple calculations at the same time. And potentially come up with unrivaled algorithms in the classical world, capable of solving the most complex problems.
"Since the 1980s, we have been trying to build a powerful quantum computer to solve some problems," John Martinis, Google's artificial intelligence researcher, told a press conference hosted by Nature.
"We demonstrated that the quantum computer has that power, the physics was right, and companies will now see that this technology is closer than they thought."greeted the researcher.
Quantum mechanics, governed by the physical principle of wave-particle duality, allows for a multitude of overlapping possibilities. It is difficult to understand because it is not touched at the sensible level, as Sundar Pichai summarized: "While the universe works fundamentally at the quantum level, humans do not experience it either. Many principles of quantum mechanics directly contradict what can be observed in nature, but their properties have huge potential for computing. "
However, he warns, "the road is still long between this lab experiment and tomorrow's concrete applications."
Qubit manipulation is really delicate because it is difficult to stabilize its quantum state – it requires simple, cold atoms isolated from the outside world. The more qubits, the greater the difficulty, and manufacturers are struggling today to exceed 53 qubits.
Following the leak of the study, several experts called for caution, saying that this particular calculation was "useless" and that the advent of a universal quantum computer would not be for tomorrow. The latter, if born, would in theory be capable of breaking the cryptographic systems known as "RSA" currently used by global computing. Hence the search for robust encryption, already well advanced.
Information from Google was released when IBM, the other very advanced heavyweight in the quantum race, announced that it would put a 53-qubit quantum machine, the power equivalent of Google's machine, in line with researchers and developers.