Sandia National Laboratory researchers have found that one way to reduce noise in a quantum system is to use silicon.
"The noise is reduced with silicon, and that is an advantage for this type of quantum computing, since you want to maintain coherence for as long as possible," says Sandia researcher Malcolm Carroll.
However, the researchers had difficulties isolating and manipulating silicon spins. They recently have been experimenting with controlling the number of silicon spins with a gate instead of using doping methods. "What we've done is taken the large scale field-effect transistor structure, and make it into a few-electron quantum dot," Carroll says.
The structure includes a double quantum dot. "The dots are placed next to each other, and this gate structure makes it easier to control the spins in the device," he says. Silicon also produces less noise at low temperatures, and the infrastructure already exists for producing silicon-based devices. "People are used to working with silicon, and so you have very clean environment for the electrons, further reducing unintended noise sources," says Sandia's Tzu-Ming Lu.
Carroll notes that other researchers also are developing silicon-based quantum devices. He says silicon's "approach to isolating and controlling spins is very promising and it could allow even more people to realize the benefits of using silicon in quantum computing."
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