Technology & Science

New Canadian quantum computer called twice as powerful as last one, but what does that mean?

With more qubits, researchers can solve certain problems more efficiently, and in some cases, faster. But a universal quantum computer, one that can solve a wider range of problems, is still a way off.

B.C.-based D-Wave says researchers can solve certain problems more efficiently and sometimes faster

D-Wave's new 2000 qubit system costs US$15 million. (Handout/D-Wave)

There's a new quantum computer from Canadian company D-Wave on the market — one that is said to be twice as powerful as D-Wave's previous model.

The processor in D-Wave's new computer boasts 2,000 quantum bits, or qubits — the unit used to gauge a quantum computer's power — while its previous version only had 1,000. But what, exactly, does that mean?

In short: with more qubits, researchers can solve certain problems more efficiently, and in some cases, faster. Basically, it's an improvement on what D-Wave already sells. 

But a universal quantum computer, one that can solve a wider range of problems, is still a way off.

"They have remained with the same architecture, but what they've done is they've increased its capacity for computation," explained Amr Helmy, a professor of electrical and computer engineering of the University of Toronto. he is also director of the university's Centre for Quantum Information and Quantum Control.

An 'exponential' improvement

For D-Wave's customers — which include Google and NASA — upgrading to a new quantum computer isn't like going out and buying a new, faster laptop.

Unlike traditional computers, which perform calculations using binary bits — that is, bits that either represent a 1 or 0 — the bits in a quantum computer can represent both states at the same time. Researchers say they can exploit this behaviour to perform more complex computations than traditional computers, and perform them faster, too.

Different from our current digital electronic computers, Quantum computers offer a level of power that's never existed before 5:49

"The power advance associated with this doubling of the number of bits is exponential. It's not linear," explained Helmy. "It's not like you are going to double the bits and you double the power. It doesn't work this way. It's significantly more profound."

Depending on the problem, he believes researchers could see improvements in their calculations by factors of hundreds, even thousands of times, a claim that D-Wave also made in its announcement.

However, "it's power is very much predicated by the problems you ask it to solve, so that's why this is a nominal enhancement, not a universal one," said Helmy.

Certain problems, but not all

D-Wave's computers specialize in handling certain types of problems, which is part of the reason why some are reluctant to call D-Wave a true quantum computer — one capable of solving a wide range of problems faster than traditional computers on the market now.

Meanwhile, "it is still unknown whether D-Wave's machine actually harnesses quantum mechanics to offer a computational speed-up," wrote Martin Laforest, a senior manager for scientific outreach at the University of Waterloo's Institute for Quantum Computing. He added that the new model will offer the research community the chance to perform further tests "and determine if it offers a true quantum mechanical advantage."

Others, however, disagree.

"There are very few doubts left that there are indeed quantum effects at work and that they play a meaningful computational role," Daniel Lidar, a University of Southern California researcher, told Wired in late 2015.

At present, D-Wave's computer specializes in so-called optimization problems — finding the best solution to problems as efficiently and effectively as possible. 

This is what D-Wave's new 2000 qubit processing unit looks like up close, before it's cooled to -273°C. (Handout/D-Wave)

Applications that benefit from this type of search routine typically involve vast amounts of data. Helmy pointed to software verification, which can involve time-consuming bug hunting through huge libraries of code, and cybersecurity, where researchers sometimes need to sift through massive volumes of network traffic looking for a needle in a digital haystack, as two examples.

Indeed, the first customer for D-Wave's new 2,000 qubit system: a cyber security company called Temporal Defense Systems, which said the system was valued at $15 million US.

D-Wave has said that it expects to double the number of qubits in its systems every two years, having previously announced its 1,000 qubit system in 2015. New Scientist reported that the company is already working on its 4,000 qubit model, which is expected to make it even easier for scientists to execute more complex problems.

About the Author

Matthew Braga

Senior Technology Reporter

Matthew Braga is the senior technology reporter for CBC News, where he covers stories about how data is collected, used, and shared. You can contact him via email at matthew.braga@cbc.ca. For particularly sensitive messages or documents, consider using Secure Drop, an anonymous, confidential system for sharing encrypted information with CBC News.