State transfer in dissipative and dephasing environments
School of Science, Xi'an University of Posts and Telecommunications, Xi'an, 710061, P.R. China
Corresponding author: a firstname.lastname@example.org
Revised: 14 April 2010
Published online: 6 July 2010
By diagonalization of a generalized superoperator for solving the master equation, we investigated effects of dissipative and dephasing environments on quantum state transfer, as well as entanglement distribution and creation in spin networks. Our results revealed that under the condition of the same decoherence rate γ, the detrimental effects of the dissipative environment are more severe than that of the dephasing environment. Beside this, the critical time tc at which the transfer fidelity and the concurrence attain their maxima arrives at the asymptotic value t0 = π/2λ quickly as the spin chain length N increases. The transfer fidelity of an excitation at time t0 is independent of N when the system subjects to dissipative environment, while it decreases as N increases when the system subjects to dephasing environment. The average fidelity displays three different patterns corresponding to N = 4r + 1, N = 4r-1 and N = 2r. For each pattern, the average fidelity at time t0 is independent of r when the system subjects to dissipative environment, and decreases as r increases when the system subjects to dephasing environment. The maximum concurrence also decreases as N increases, and when N ∞, it arrives at an asymptotic value determined by the decoherence rate γ and the structure of the spin network.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010