A common blue pigment could change the face of quantum computing

A common blue pigment used in the 5 pound note could have an important role to play in the development of a quantum computer, according to a paper publishes in the journal Nature and news from UCL. 

The pigment, copper phthalocyanine (CuPc) is a low cost organic semiconductor that is found in many household products. Crucially, it can be processed into a thin film that can be readily used for device fabrication, a significant advantage over similar materials that have been studied previously. 

Researchers from the London Centre for Nanotechnology at UCL and the University of British Columbia have shown that the electrons in CuPc can remain in 'superposition'- an intrinsically quantum effect where the electron exists in two states at once- for surprisingly long times, showing this simple dye molecule has potential as a medium for quantum technologies. 

Lead author Marc Warner from the London Centre for Nanotechnology, said: "In theory, a quantum computer can easily solve problems that a normal, classical, computer would be able to answer in the lifetime of the universe. We just dont know how to build one yet. Our research shows that a common blue dye has more potential for quantum computing than many of the more exotic molecules that have been considered previously."

Dr Warner added: "The properties of copper phthalocyanine make it of interest for the emerging field of quantum engineering, which seeks to exploit the quantum properties of matter to perform tasks like information processing or sensing more effectively than has ever been possible". 

There some important attributes that CuPc possesses. Attributes that could exploit the spin of electrons, rather than their charge, to store and process information which are highly desirable in a more conventional quantum technology. A simple example is, consider a pigment, it can strongly absorbs visible light and is easy to modify chemically and physically, so its magnetic and electrical properties can be controlled.