  By considering distance-regular graphs as spin networks, we investigate the
state transfer fidelity in this class of networks. The effect of environment on
the dynamics of state transfer is modeled using Milburn's intrinsic decoherence
[G. J. Milburn, Phys. Rev. A 44, 5401 (1991)]. We consider a particular type of
spin Hamiltonians which are extended version of those of Christandl et al
[Phys. Rev. A 71, 032312 (2005)]. It is shown that decoherence destroys perfect
communication channels. Using optimal coupling strengths derived by Jafarizadeh
and Sufiani [Phys. Rev. A 77, 022315 (2008)], we show that destructive effect
of environment on the communication channel increases by increasing the
decoherence rate, however the state transfer fidelity reaches a steady value as
time approaches infinity which is independent of the decoherence rate.
Moreover, it is shown that for a given decoherence rate, the fidelity of
transfer decreases by increasing the distance between the sender and the
receiver.
