  We propose a model for the electric current in graphene in which electric
carriers are supplied by virtual particles allowed by the uncertainty
relations. The process to make a virtual particle real is described by a weak
value of a group velocity: the velocity is requisite for the electric field to
give the virtual particle the appropriate changes of both energy and momentum.
With the weak value, we approximately estimate the electric current,
considering the ballistic transport of the electric carriers. The current shows
the quasi-Ohimic with the minimal conductivity of the order of e^2/h per
channel. Crossing a certain ballistic time scale, it is brought to obey the
Schwinger mechanism.
