14 December 2011—Quantum computers have the potential to solve seemingly intractable problems in no time flat. But a big stumbling block on the path to practical quantum computing is figuring out how to observe the tiny quantum signals that drive computation. In an advance that may make that observation easier, a group at Aalto University, in Finland, has created a new kind of microwave amplifier based on a mechanical resonator—essentially a nanometer-scale tuning fork.
“When you have microwave signals on the level of a single quantum, you can’t manipulate them with your bare hands—you need to amplify the signal,” says Francesco Massel, a postdoctoral researcher at Aalto who worked on the device. But today’s amplifiers boost those signals at a cost, sometimes drowning them out with noise from the amplifiers themselves. “Our device adds, at least in principle, the minimum possible amount of noise dictated by the laws of quantum mechanics,” says Massel.