Quantum mechanics revolutionized thinking in physics in the late 1920s. Today it’s poised to change the world of computing.
Traditional computers operate in a world that we consider normal. Things in that world exist in an understandable and carefully defined state. Take a light bulb, for example. That bulb is either on or off; it can’t be both. Classical computers exist in the same way. The computer bit – the smallest unit of storage – can hold a value of either 0 or 1, but not both and nothing in between.
Enter quantum mechanics, the branch of physics that deals with the behavior of subatomic particles. In quantum mechanics, we find ourselves down the rabbit hole, experiencing a world in which something can be both a wave and a particle; particles can tunnel through walls and appear and disappear; objects can have negative mass; an unobserved photon can exist in all possible states simultaneously. It’s whacky. As Bohr himself said, “Anyone who is not shocked by quantum theory has not understood it.”
But here’s the thing. Even though we think of quantum mechanics as confined to the realm of the very small, it can be used to change the very nature of computing. That’s where qubits come in.
The qubit – quantum bit – is the quantum equivalent of the classical computer bit. Qubits exist in what is called a superposition of states. As a result, they can look at many different variables simultaneously.
What does this mean for computing? Well, for one thing, it may solve the problems we are encountering with the massive amounts of data we continue to collect. Quantum computers will be able to make calculations, such as those required for optimization studies, that would take a billion years for a classical electronic binary computer to complete. Google, for example, has announced that its quantum computer is 100 million times faster than any classical computer in its lab.
Furthermore, quantum computers may save huge amounts of energy. The operation of a quantum processor requires remarkably little power—only a tiny fraction of a microwatt. Most of the energy cost of quantum computing goes toward running the refrigeration unit that keeps the quantum processor cool. Quantum computers, it should be noted, are very fragile.
But perhaps the most critical impact of quantum computing lies with its effect on data security. According to a research team from IBM, quantum computers can instantly break the encryption of data protected by even the strongest security protocols currently available. Fortunately, it also appears that quantum computers may be able to create hack-proof forms of encryption.
Experts also note that quantum computers won’t be necessary – or even the best choice – for every type of application. Classical computers are just fine for browsing the Internet, creating spreadsheets, or writing the great American novel. Unless you plan to tackle a problem that currently requires a supercomputer, you probably won’t need a quantum device. But quantum computers will be a reality in the not too distant future. Where we’ll go from there could well be a ride through Wonderland.