IBM's five five qubit processor IBM Research

Quantum computing is computing at its most esoteric. It's an experimental, enormously complex, sometimes downright confusing technology that's typically the domain of hardcore academics and organizations like Google and NASA. But that might be changing.

Today, IBM unveiled an online service that lets anyone use the five-qubit quantum computer its researchers have erected at a research lab in Yorktown Heights, New York. You can access the machine over the Internet via a simple software interface—or at least it's simple if you understand the basics of quantum computing. This new service is hardly something the everyday consumer will use, but it's a big deal for the many researchers now working to build a practical quantum computer—a computer that moves beyond just 1s and 0s to become exponentially more powerful than today's machines. In that sense, IBM is indeed striving to bring quantum computing to the world at large.

'I think that someone out there will learn things about the behavior of this quantum computer that its developers never thought of.'

Yes, the service is a way for IBM to show off its quantum computer, to have outsiders verify and approve its work—something that's particularly important when you're dealing with the hard-to-pin-down dynamics of quantum systems. But David DiVincenzo, a professor at the Institute for Quantum Information at RWTH Aachen University and one of quantum computing's earliest pioneers, believes the service will lead to more. "I think that someone out there will learn things about the behavior of this quantum computer," he says, "that its developers never thought of."

That's an important thing as researchers seek to unlock new realms of technology with this kind of machine, including everything from understanding DNA sequences to predicting the rise and fall of the stock market. Some aim to simulate the way individual molecules interact, while others hope that quantum computers will extend the reach of machine learning. That's what Google and NASA are exploring with their $10 million D-Wave machine, a somewhat controversial creation that exhibits quantum properties in at least some situations.

IBM Research

Meet the Qubit

Today's computers store data in extremely small transistors. Each transistor can hold a single "bit" of information: a 1 or a 0. But about thirty years ago, scientists proposed a machine that could go beyond that binary, a machine that could store data in a system that obeys the seemingly magical principles of quantum mechanics. Instead of just a 1 or a 0, a "qubit" could store both at the same time, thanks to what's called the superposition principle.

By extension, two qubits could hold four values simultaneously: 00, 01, 10, and 11. And if you keep adding qubits, you could, in theory, build a machine far more powerful than any that exists today. "These are things you can't explain with regular logic," says Jerry Chow, the former Yale researcher who helps oversee IBM's quantum computing work. "Quantum computing and quantum algorithms are all about: how do you harness that?"

But that kind of ultra-powerful machine doesn't yet exist. Qubits, you see, are slippery things. If you try to observe the state of a quantum system, it "decoheres," falling into one state or the other. It no longer holds both a 0 and a 1. It holds only a O or a 1, like the classical computers of today. To build a true quantum computer, researchers must harness the probability that a qubit will decohere into one state versus the other.

The Same Result Each Time

There are many ways of doing this, and though none has truly cracked the problem, some are quite promising. IBM has built a quantum computer that operates by dropping superconducting circuits into an enormous sub-zero refrigerator, and it spans five qubits. But now, in sharing this machine with the world at large, the company hopes to accelerate its progress, aiming to extend its power to 50 or possibly 100 qubits.

These are things you can't explain with regular logic. Jerry Chow, IBM

According to David Cory, a professor with the University of Waterloo's Institute for Quantum Computing, this sort of online quantum computer—a quantum cloud service, if you will—is pretty much unprecedented. Building such a service, he explains, is far more difficult than you might expect. "It's not a simple thing to do," he says. "Quantum systems are really quite delicate."

And, he adds, IBM has done it right. The service is fronted by an interface that's remarkably easy to use. "Any student that has a first introduction to quantum computing would understand how to interact with this device," Cory says.

Cory spent the weekend using the new service, and what struck him was that the system was so consistent—that it reached the pretty much same result each time he ran a test. That's not a big deal in the world of classical computing. Your laptop does that countless times a second. But in the world of quantum computing, which is all about capturing probabilities, consistency is a sign of progress. Now, with this service available to the larger community, perhaps more progress is on the way.