  Using the AdS/CFT correspondence we study transport coefficients of a
strongly-coupled (2 +1)-dimensional field theory at {\it zero} temperature and
finite charge density. The field theory under consideration is dual to the
extremal Reissner-Nordstrom AdS_4 black hole in the bulk. We show that, like
the cases of scalar and spinor operators studied in \cite{Faulkner:2009wj}, the
correlators of charge (vector) current and energy-momentum (tensor) operators
exhibit scaling behavior at low frequency. The existence of such low frequency
behavior is related to the fact that the near-horizon geometry of the extremal
black hole background has an AdS_2 factor. We carefully calculate the shear
viscosity (at zero temperature) and show that the ratio of the shear viscosity
to the entropy density takes the value of 1/4\pi. Because of the AdS_2 factor,
we argue that this result stays the same for all d-dimensional boundary field
theories dual to the extremal Reissner-Nordstrom AdS_{d+1} black holes. Also,
we compute the charge conductivity at zero temperature. The limiting behavior
of the conductivity for small frequencies is also attributed to the near
horizon AdS_2 factor and is argued to hold regardless of the dimension of the
zero-temperature boundary field theory. Finally, using the extremal dyonic
AdS_4 black hole as the background, we extract the conductivity in the presence
of a constant magnetic field.
