PARIS: Scientists claimed on Wednesday to have achieved a near-mythical state of computing in which a new generation of machine vastly outperforms the world’s fastest super-computer, known as “quantum supremacy”.

A team of experts working on Google’s Sycamore machine said their quantum system had executed a calculation in 200 seconds that would have taken a classic computer 10,000 years to complete.

A rival team at IBM has already expressed scepticism about their claim.

But if verified and harnessed, the Google device could make even the world’s most powerful supercomputers — capable of performing thousands of trillions of calculations per second — look like an early 2000s flip-phone.

Regular computers, even the fastest, function in binary fashion: they carry out tasks using tiny fragments of data known as bits that are only ever either 1 or 0.

But fragments of data on a quantum computer, known as qubits, can be both 1 and 0 at the same time.

This property, known as superposition, means a quantum computer, made up of several qubits, can crunch an enormous number of potential outcomes simultaneously.

The computer harnesses some of the most mind-boggling aspects of quantum mechanics, including a phenomenon known as “entanglement” — in which two members of a pair of bits can exist in a single state, even if far apart.

Adding extra qubits therefore leads to an exponential boost in processing power.

In a study published in Nature, the international team designed the Sycamore quantum processer, made up of 54 qubits interconnected in a lattice pattern.

They used the machine to perform a task related to random-number generation, identifying patterns amid seemingly random spools of figures.

The Sycamore, just a few millimetres across, solved the task within 200 seconds, a process that on a regular machine would take 10,000 years — several hundreds of millions of times faster, in other words.

While the peer-reviewed research has drawn plaudits, with MIT’s William D. Oliver comparing its findings in Nature to the Wright brothers’ first flights, sceptics say Google is over-selling its achievement.

Researchers at IBM, Google’s main quantum computing rival, said a supercomputer with additional disk storage can solve the random number problem in at most 2-1/2 days, with greater fidelity _ or accuracy.

They also said Google risked misleading the public by implying the new-style computers would replace existing ones.

“Quantum computers will never reign ‘supreme’ over classical computers, but will rather work in concert with them, since each have their unique strengths,” Dario Gil, director of research at IBM, wrote in a blog

Torsten Siebert, manager of the quantum computing research programme at Germany’s Fraunhofer Society, said Google had achieved impressive fidelity in its experiment involving a large number of qubits.

Ultimately, he said, quantum computers were likely to work in harness with classical computers _ with each playing to its strengths.

Published in Dawn, October 24th, 2019