Entanglement dynamics of three-qubit states in noisy channels

We study entanglement dynamics of the three-qubit system which is initially prepared in pure Greenberger-Horne-Zeilinger (GHZ) or W state and transmitted through one of the Pauli channels s_zsigma_z, s_xsigma_x, s_ysigma_y or the depolarizing channel. With the help of the lower bound for three-qubit concurrence we show that the W state preserves more entanglement than the GHZ state in transmission through the Pauli channel s_zsigma_z. For the Pauli channels s_xsigma_x, s_ysigma_y and the depolarizing channel, however, the entanglement of the GHZ state is more resistant against decoherence than the W-type entanglement. We also briefly discuss how the accuracy of the lower bound approximation depends on the rank of the density matrix under consideration.