How to actually understand quantum computing

Quantum computing is becoming an incredible force for problem-solving and computing for a wide range of industry purposes, but it’s not always clear to a normal person exactly why it’s so special. To learn more about what sets quantum computing apart from traditional computing, we spoke with Michael Brett, chief executive officer at quantum computing software company QxBranch.

ABERMAN: What is quantum computing?

BRETT: Quantum computing is an incredibly exciting new technology, and we’re at this inflection point where it’s a technology that’s been developed in universities and research labs all around the world for the past thirty years or so. But just in the last couple of years, we’ve seen the technology transition out of those research labs and into very intensive research and development efforts to actually create these new types of computers.

And what’s so interesting about a quantum computer is that, unlike a classical computer, what we’re used to in our phones and laptops, quantum computers use a different kind of physics. It’s the behavior of the very very small, of the subatomic world, and by using a different kind of physics, that allows us to run a different kind of math, and then a different kind of algorithm on top of that, and solve problems in an entirely different way to what we do with classical computers.

ABERMAN: Now, as a practical matter, to this point, technology has all been about binary. It’s a yes-no. You can put a lot of yes-nos together, and that’s how you get a computer program. or you get a circuit, and so forth. My understanding is that quantum computing, because of the way it works, you just have a lot more possible outcomes, and as a result, you can, what, process information quicker, capture more nuance? What is it about it that makes it so exciting?

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BRETT: I’ll use an analogy here to help explain it. So, think of the lights in your kitchen. And so, when you walk into the kitchen in the morning, and you turn the lights on, let’s say you’ve got two light switches to work with. And so, in a classical computer, it’s a traditional light switch. It’s either on or off. And if you’ve got two light switches, there are four possible combinations. They can both be on, both be off, one on one off, the other one on and the other off, et cetera.

So, in a classical computer, you’ve got these bits to work with. In a quantum computer, think of it instead as having two dimmer switches that are next to each other. And so, rather than just having four possible combinations, you’ve essentially got an infinite number of combinations as you configure those two dimmer switches to get the lighting exactly right in your kitchen.

That’s why this is so interesting to us, it’s a different kind of physics that we’re working with on the fundamental level of building these computers, that allows us to program more information into the problem that we’re trying to solve. And then, manipulate that information in a different kind of way, and extract new answers from that.

ABERMAN: When I hear that quantum computing is coming about, does that mean that we’re going to end up with different types of chips, different types of boxes? I mean, how is this going to manifest itself?

BRETT: Yeah, this is a really exciting time for quantum computing, because we’ve now got real chips to work with, and real hardware to play with. So, my company, QxBranch, we’re a partner in a number of different quantum computing networks, one with IBM, another with a startup company called Rigetti that we’ve just announced, and these companies are building hardware that we can use to program quantum computing applications on top of. And they look really exotic. It looks really cool.

If you take a look at some photos of quantum computers, they’re about the size of an elevator. It looks like this crazy shrink ray thing inside of it, and then at the bottom of the shrink ray is the actual quantum computing chip. The whole apparatus around it is cooling systems that chill these chips down to almost absolute zero. And so, it’s quite an exotic-looking device. But the way that we interact with it as a software program is quite normal. It’s on the cloud. There’s a server that we interact with.

You send out programs to it, it does calculations, and we get the results back from it. So, I don’t think we’re going to see quantum computers in our phones anytime soon, but we’ll be able to access those quantum computers through the cloud, on Amazon, Google, in Microsoft Cloud, et cetera, to be able to solve different kinds of problems with them.

ABERMAN: Give me an example. I’ve heard encryption is a big one, with breaking encryption, but what are some of the practical ways quantum computers can change our lives.

BRETT: So there are some problems that, even with all computing power we have access to, that are still extremely difficult to solve. They’re extremely computationally expensive, in that they take a lot of time, or take a lot of energy to solve problems. And so, to give you a really practical example, think of a logistics problem where you’re delivering a hundred packages around Washington, D.C. this afternoon. What’s the optimal route to take to deliver all of those packages? That’s an extremely challenging computer science problem to go through that.

One of the reasons it’s challenging is that there’s no way to break it up into smaller problems. To get the perfect answer, you need to check every possible solution, of a hundred possible combinations. And then if, late in the day, you add another package to the truck, and all of a sudden there’s one hundred and one packages, the problem becomes twice as difficult to solve. Again, it becomes exponentially more difficult.

And so, these are the kind of problems, the class of problems, that quantum computing is really well-suited to solving, that we can use that different physics that’s operating at the base level to encode more information, solve that problem using a different kind of algorithm, and be able to save a lot of time and energy cost than in calculating that with classical computers.

ABERMAN: So, people who say that quantum computing really is next big thing are not exaggerating?

BRETT: Not at all. This is a revolution in computer science. It’s giving us an entirely new tool in the toolkit of computer science to work with. These computers will work in cooperation with classical computers. So, we’ll write programs that the use power of both, and each computer is suited to some problems, to different kinds of problems. But it really will give us a new, foundational toolkit to work with.

ABERMAN: I really appreciate you coming in, Michael. It sounds to me like, yet again, here in D.C., we’re at the head of things that we did we didn’t even imagine we were. So, thanks for coming in.

BRETT: It’s been a pleasure, thank you.