The British five-pound note is worth about $8, give or take a few cents, but the blue pigment used on the bills may prove invaluable to the field of quantum computing.
A team of UK and Canadian researchers have determined that the copper phthalocyanine molecules in the pigment can hold the superimposed state of a quantum bit (holding two states at once) for as long or longer than other materials. That means the material could be used as a semiconductor in future quantum computers, which could work faster than existing technology.
Copper phthalocyanine can also be produced as a thin film, which could be used to incorporate the substance into electronic devices.
According to the research, published in Nature in October, the lifetimes of the quantum bits measured were “surprisingly long” for the low-cost blue pigment. In the tests, the molecules were able to maintain electron spins in both the up and down states. In quantum computing, the spin states could be used to store bits of information.
At 5 degrees Kelvin, the spins remained parallel to a magnetic field for 59 milliseconds; the superimposed spin state lasted 2.6 milliseconds.
The team included scientists from the London Centre for Nanotechnology and Department of Physics and Astronomy, University College London; Imperial College London; and the University of British Columbia in Vancouver.