Software improvements keep quantum cats at bay


Potentially dead or alive in the water for now

It seems there is still life in conventional computing as a better-written algorithm has beaten Google’s Sycamore quantum computer.

In 2019, the Sycamore computer was used by Google to demonstrate how a quantum computer could accomplish a task that would be impossible for ordinary computers.

At the time, Sycamore achieved quantum supremacy in a task that involved verifying that a sample of numbers emitted by a quantum circuit had a truly random distribution, which he was able to complete in 3 minutes and 20 seconds. The Google team said that even the most powerful supercomputer in the world at the time, IBM’s Summit, would take 10,000 years to achieve the same result.

Boffin Pan Zhang and his colleagues at the Chinese Academy of Sciences took on the challenge without the need for a quantum computer. They just used better coding.
The researchers found that they could skip some of the computations without affecting the final result, significantly reducing computational requirements compared to previous best algorithms.

The researchers ran their algorithm on a cluster of 512 GPUs (graphics processing units), completing the task in about 15 hours. Although it’s significantly longer than Sycamore, they say it shows that a classic IT approach is still practical and doesn’t require the use of any cats.

They calculated that if they were able to run their algorithm efficiently on an exascale supercomputer, it could solve the problem in “tens of seconds”, beating Sycamore’s time.

Zhang says his team’s algorithm is “massively more efficient than existing methods,” but admits that classical computers are unlikely to keep pace with quantum machines for some tasks. “Eventually, quantum computers will have overwhelming advantages over classical computing in solving specific problems,” he says.

In a statement, Sergio Boixo, Principal Scientist at Google Quantum AI, said: “In our 2019 paper, we said classical algorithms would improve…but the key point is that quantum technology is improving exponentially. faster. We therefore do not believe that this classical approach can keep pace with quantum circuits in 2022 and beyond, despite significant improvements in recent years.