  Within the framework of the AdS/CMT correspondence asymptotically anti-de
Sitter black holes in four space-time dimensions can be used to analyse
transport properties in two space dimensions. A non-linear renormalisation
group equation for the conductivity in two dimensions is derived in this model
and, as an example of its application, both the Ohmic and Hall DC and AC
conductivities are studied in the presence of a magnetic field, using a bulk
dyonic solution of the Einstein-Maxwell equations in asymptotically AdS$_4$
space-time. The ${\cal Q}$-factor of the cyclotron resonance is shown to
decrease as the temperature is increased and increase as the charge density is
increased in a fixed magnetic field. Likewise the dissipative Ohmic
conductivity at resonance increases as the temperature is decreased and as the
charge density is increased. The analysis also involves a discussion of the
piezoelectric effect in the context of the AdS/CMT framework.
