WE ARE ALL DESIGNISTS NOW:

A computer that thinks like the universe: If an atomic-scale computer can be built, it won't just create a faster machine: it will help us think like the universe (Joshua Rothman, November 26, 2011, Boston Globe)

With quantum computing, today's researchers are trying to perform a sort of jujitsu. Improbably, they want to use the uncertain, counterintuitive, probabilistic world of quantum mechanics to perform calculations -- and to break through the practical limits of modern, "classical" computers.

Unlike a computer circuit, atoms, electrons, and other atomic or subatomic particles aren't always hard and concrete; instead, they are more like clouds of probability. Get small enough, and you don't exist here or there; you exist here and there, simultaneously. A quantum computer builds this strange kind of reality right into its hardware. In a normal computer, each tiny switch represents a "bit," reading either "0" or "1." The basic unit of quantum computing is called a "qubit" -- an atom, electron, or other tiny particle that might be in one state, or another, or, crucially, somewhere in between. Quantum computing relies upon the fact that qubits can contain far more information than bits -- not just 1s and 0s, but combinations of the two. If we could learn to harness their processing power, we could use qubits to work far faster, and do far more, than we could with a traditional computer.

Qubits, unfortunately, are very, very hard to work with. Because they're so small, they're easily jostled; if that happens, the computer "decoheres" and becomes a bunch of atoms in a pile. They are exquisitely sensitive; look at them too soon, and you can change the result. And they are very hard to program. One of the best demonstrations of quantum computing to date, done in 2001 in an IBM lab in California, used a huge magnet and five atoms to figure out a very simple piece of arithmetic: that the factors of 15 are 3 and 5.

But what tantalizes some researchers is that, compared to a traditional computer, a quantum computer would operate much closer to the way the universe works. 

Posted by oj at December 4, 2011 6:10 AM
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