  The carriers in graphene tuned close to the Dirac point envisage signatures
of the strongly interacting fluid and are subject to hydrodynamic description.
The important question is whether strong disorder induces the metal-insulator
transition in this two-dimensional material. The bound on the conductivity
tensor found earlier within the single current description, implies that the
system does not feature metal-insulator transition. The linear spectrum of the
graphene imposes the phase-space constraints and calls for the two-current
description of interacting electron and hole liquids. Based on the
gauge/gravity correspondence, using the linear response of the black brane with
broken translation symmetry in Einstein-Maxwell gravity with the auxiliary
U(1)-gauge field, responsible for the second current, we have calculated the
lower bound of the DC-conductivity in holographic model of graphene. The
calculations show that the bound on the conductivity depends on the coupling
between both U(1) fields and for a physically justified range of parameters it
departs only weakly from the value found for a model with the single U(1)
field.
