The tech industry’s push to develop large-scale quantum computers with the capability to outperform current hardware is advancing by leaps and bounds.

The latest development comes courtesy of Google LLC, which on Monday unveiled a quantum processor with 72 qubits (pictured) that ranks as the largest of its kind to date by a sizable margin. The runner-up is a chip fabricated by IBM Corp. last year that includes 50 qubits. 

Qubits are the quantum equivalent of bits and are distinguished by their ability to represent three possible data values instead of the just usual two, one and zero. This seemingly small difference could add up massively in a hypothetical large-scale quantum machine. So much so, in fact, that it’s believed such systems would be capable of solving problems too difficult for even the most powerful supercomputers in existence today.

Scientists refer to this theoretical performance advantage as “quantum supremacy,” which is what Google hopes to achieve with the new chip. Dubbed Bristlecone, the processor is intended to provide a testbed for the company’s researchers to explore how the full potential of quantum computing can be realized. 

Integrating a sufficiently large number of qubits onto a chip is just one of the requirements that need to be addressed. Another is ensuring that the system handles data reliably enough to maintain a high standard of accuracy, which is no small task given the fragility of qubits. Most quantum processors are so sensitive to outside interference that they must be kept at temperatures near absolute zero.

For the sake of reliability, Google based Bristlecone on an earlier 9-qubit system it had developed that demonstrated an error rate as low as 0.6 percent. The company has also developed a specially designed benchmarking tool to measure the new processor’s accuracy. It will allow researchers to check calculations with a simulated quantum computer running on conventional hardware.

In a blog post, Google scientist Julian Kelly wrote that the goal is to have Bristlecone match the accuracy of its 9-qubit predecessor. He also divulged that the company is “cautiously optimistic” it will be able to achieve quantum supremacy using the chip further down the road.

That would represent a historic breakthrough and a big step toward building the kind of ultrapower quantum computers that presently exist only in science fiction. Such machines would enable scientists to carry out research at a level not possible with current hardware, but they’d also create new risks. It’s estimated that a 4,000-qubit machine could break RSA-2048, the go-to encryption technology used to protect data today.

Image: Google