When will quantum computers be in our pockets?

05 November 2019

Question

"Quantum computing is here! But when might we have quantum computers in our pockets, or on our desktops?"

Tech expert Peter Cowley took on this question...

"Quantum computing is here! But when might we have quantum computers in our pockets, or on our desktops?" Tech expert Peter Cowley took on this question...

Peter Cowley - Yes. Okay. Well, quantum computing hit the headlines in the last week or so because Google came up with a new version called 'Sycamore', which was 53 cubits. Very briefly - and non-technically - a "bit" normally is 0 or 1. A "cubit" - a quantum bit - can have multiple states. So say it has a thousand, which is the number they're talking about, two together there's a million, whereas two digital bits only has four states. So Google has created this thing which they claim will do a calculation that takes 200 seconds, which would normally take 10000 years - so that's pretty quick!

IBM came back and said, look we've got a quantum computer and we don't agree with this and we think that you actually should be comparing 200 seconds with two and a half days. Still a big difference. The point is what this quantum computer looks like - and there are some pictures on the Internet - basically it runs at one 15000th of a degree above absolute zero. That's not going to be easy to get in your pocket! So 15 millikelvin! There's also a few other problems: the cubit itself, if you've got a nought or a one in your hard disk or on your mobile phone, you want it to stay there. The decay time of cubit is 10 microseconds, so it needs refreshing quite quickly. It also randomly will change state in a way that don't really understand yet. So you need a lot of error correction. So they're saying that it'll take about 10 years before you get a big enough quantum computer in the lab to actually do something, and that's going to be running at basically absolute zero, and it's going to take a lot of energy. So I have no clue how long before it gets into our pockets!

Chris Smith - Richard...

Richard Hollingham - Well I just have a question about this. Is there competition. You mentioned IBM and Google, because a lot of these things - I mean, I was talking about space and the space race - a lot of these things happen when you've got competition - people competing - and suddenly things get faster and faster.

Peter Cowley - You can buy a quantum computer from a company in Canada actually, I've forgotten the name now, but only a few bits long. The point is that it is it's sort of on the hype curve at the moment. It's going up there, if anyone knows about the Gartner hype curve - there's no doubt it will be of use. They say, for instance, that a quantum computer will be hard to crack any cryptology in the world instantaneously. That means nothing is secret any longer anyway. Now, of course, people are working on stopping that happening in all kinds of different ways. It's a very long way from any form of commercial use, but, yeah, competition does help...

Chris Smith - Peter thank you very much indeed.