Date: Fri, 24 May 2013 05:15:24 +0200
- Computing and software
Quantum computing: A quantum hop
Not a leap, perhaps, but two important steps on the way to making quantum computing practical
SOME technologies seem a long time coming. Their story has a familiar script: a breakthrough is hailed; overblown expectations are aroused; disappointment follows. Away from the public’s impatient gaze, however, tinkering scientists turn out incremental improvements, furtively catching up with the revolutionary rhetoric of yore. This appears to have been the case with the sequencing of the human genome. It also illustrates the recent history of quantum computing.
An ordinary computer stores and processes information using bits, which take the value of either one or zero (physically represented by different voltages of electric current). In the bizarre world of quantum mechanics, however, subatomic particles can exist in several states at once. Such “superposition” means, for instance, that the property of an electron known as its spin can be not only “up” (representing, say, one) or “down” (representing zero) but also some combination of the two. In quantum computing, such superposed values are named qubits. ...