Graphene is really quantum

Some 'non-locality' is claimed with the electrons in graphene [Science 15 April 2011: 328-330]. The experimenters measure the voltages between two electrodes that are far away from the region where the currents are suppsed to flow. And the voltage does not vanish at even room temperature, which is not possible for classical electrons. They associate this with the strongly coherent motion of the graphene electrons. They are so quantum !

In their experiments, an electrical current is passed between two electrodes in close proximity to each other (see the figure, upper inset), and they detect a voltage far away from those electrodes. In an ordinary material under the same conditions (at room temperature and small magnetic fields), this would not happen because the electrons are incoherent and behave classically. After a few collisions with impurities in the system, the electrons would lose their phase information and undergo random walk. To reach nonlocal contacts, this would be a walk too far, and no voltage would be generated. This indicates that graphene is behaving in a quantum mechanical way and creating a nonlocal voltage under unexpected conditions. How is this possible? [http://www.sciencemag.org/content/332/6027/315.full]