  By making use of a low-energy effective model of Weyl semimetals, we show
that the Fermi arc transport is dissipative. The origin of the dissipation is
the scattering of the surface Fermi arc states into the bulk of the semimetal.
It is noticeable that corresponding scattering rate is nonzero and can be
estimated even in a perturbative theory, although in general the reliable
calculations of transport properties necessitate a nonperturbative approach.
Nondecoupling of the surface and bulk sectors in the low-energy theory of Weyl
semimetals invalidates the usual argument of a nondissipative transport due to
one-dimensional arc states. This property of Weyl semimetals is in drastic
contrast to that of topological insulators, where the decoupling is protected
by a gap in the bulk. Within the framework of the linear response theory, we
obtain an approximate result for the conductivity due to the Fermi arc states
and analyze its dependence on chemical potential, temperature, and other
parameters of the model.
