December 19, 2014

How nanostrings and quantum bits go ‘out of tune’

The key to quantum computing is preserving quantum information. A classic computer bit has two states: 1 or 0. A quantum bit however has the special property that it can be not just 1 or 0, but also 1 and 0 at the same time, and, in fact, everything in between. The biggest challenge for quantum researchers is that a qubit in these ‘in-between’ states lose their quantum information very quickly due to a process called ‘decoherence’ arising from disturbances of the qubit from its surroundings. Researchers from Delft University of Technology studied how decoherence could be measured in mechanical resonators, basically tiny vibrating strings made from carbon nanotubes, and found that the processes of decoherence in a vibrating nanotube can be thought of in a very similar way as the decoherence of a quantum bit. Using this similarity, you can visualize the loss of quantum information by thinking about a vibrating guitar string. Their work was reported in Nature Communications on Friday, December 19th.