Quantum Computer
Quantum Computer
A technology that uses quantum mechanics to potentially speed up certain calculations once impractical to solve.
In Simple Terms
A quantum computer is a next-generation computer that may perform certain calculations at remarkable speed by harnessing the physics of the tiny quantum world. Unlike conventional computers, which represent information as either "0" or "1," it uses "qubits" that can hold both in an overlapping state. Using this overlap, it can greatly shorten the steps needed to solve certain problems. Because this could put encryption such as the widely used RSA at risk, new encryption techniques are being researched, and uses in drug discovery and materials science are also expected.
Behind the Name
The name "Quantum Computer" combines "quantum" and "computer." The word "quantum" relates to the world of extremely small things — atoms, electrons, and the like — described by the laws of physics known as quantum mechanics, and a "computer" is a machine that performs calculations. It earned this name because it computes by harnessing the rules of that tiny quantum world.
Take a Closer Look!
A quantum computer is a next-generation computer that may deliver extraordinary computing power on certain kinds of problems by using the laws of physics that govern the tiny world of quantum mechanics. The PCs and smartphones we use every day are called "classical computers," and their underlying mechanism is fundamentally different.
An ordinary computer calculates using "bits," which represent information as either "0" or "1" — much like a switch being on or off. A quantum computer instead uses "qubits," which can hold a curious state where "0" and "1" overlap. When measured, a qubit settles on either "0" or "1," but during a calculation it carries components of both, and computing is done by skillfully manipulating that state. This property is called "superposition," and used well, it can greatly shorten the steps needed to reach the answer for certain kinds of problems.
One area where the impact is considered especially large is security. Encryption such as RSA, widely used in internet communication, is built on the premise that it would take ordinary computers far too long to crack. But if large, high-performance quantum computers are realized in the future, there is a risk that such encryption could be broken. For that reason, research into new encryption that can withstand quantum computers is being pursued alongside it.
There are other uses too: in fields such as drug discovery and materials science, researchers are exploring how to simulate the complex behavior of molecules.