Researchers at Harvard University in Cambridge, Mass., have demonstrated carbon nanotube-based quantum dots that can be defined and controlled electrostatically and could be used for quantum computing systems.
Previous nanotube-quantum dot studies investigated quantum dots formed by nanotube defects or by tunnel barriers in a metal/nanotube interface. With these methods, it was not possible to independently control device parameters, and there also were strict constraints on device design. The new technique gets around these restrictions because the quantum dots are defined by controlling gates...