Factorization law for entanglement evolution of two qubits in non-Markovian pure dephasing channels

The entanglement evolution of two qubits in local, two-sided non-Markovian pure dephasing channels is investigated. It is found that for the two-sided pure dephasing channel case, when the qubits are initially prepared in a general class of states, whether pure or mixed, the entanglement can be expressed as the products of initial entanglement and the channels' action on the maximally entangled state. This provide us a good approximation to characterize the entanglement dynamics of arbitrary states to some extent. (C) 2011 Elsevier B.V. All rights reserved.