An amplifier that’s quantum quiet

December 15, 2011 | Source: IEEE Spectrum
The Aalto amplifier

The Aalto amplifier consists of a meandering microwave cavity coupled to an aluminum resonator. The two components are separated by a gap just a few nanometers wide (credit: Mika Sillanpää/Low Temperature Laboratory/Aalto University)

In an advance that may make observing observe the tiny quantum signals that drive quantum computation easier, engineers at Aalto University in Finland have created a new kind of  sensitive, low-noise microwave amplifier based on a mechanical resonator — essentially a nanoscale tuning fork.

The mechanical design eliminates electronic flicker noise, allowing for reducing noise down to 20 quanta. A future design will further reduce thermal noise by cooling the resonator.

Ref. F. Massel et al., Microwave amplification with nanomechanical resonators, Nature, 2011 [doi: 10.1038/nature10628]