Computers get faster as the transistors on microchips get smaller and closer together. In about 20 years, transistors will shrink down to the size of atoms. When that happens, the laws of physics will demand another revolution. This is when the laws of quantum mechanics, a branch of physics that describes the interaction of objects smaller than molecules, wreak havoc on the way chips are designed. But as quantum mechanics shuts the door on digital computers, it may also lead us to the next revolution.
Devices known as quantum computers show amazing promise.
Although they are decades from being practical, according to researchers, quantum computers may one day add previously unimagined computing power to such complex tasks as database-searching and breaking secret codes, tasks that now require powerful supercomputers. They could also allow the creation of new encryptions methods that would be, in theory, unbreakable. In one step a quantum computer can do what a conventional computer needs several to accomplish. By lining up thousands of these bits, a computer can perform complicated mathematical calculations, and even use that ability to do tasks like downloading a Web page and displaying it on a screen. But qubits can exist in several states at once, rather than one at a time.