Optimal qubit-bases for preserving two-qubit entanglement against Pauli noises

Environment-induced decoherence would shorten the transmission distance or storage time of entangled states. Enhancing the intrinsic robustness and prolonging the disentangling time of entangled states are thus of importance. We here study the problem of optimal qubit-basis under which a two-qubit state has maximal residual entanglement or longest entanglement lifetime in general Pauli channels with the probabilities of three types of errors being not all the same. It is shown that the optimal qubit-bases are not the same in different cases. The advantages of the entangled states with optimal qubit-bases are obvious, e.g., sudden death of entanglement could be avoided. These results are expected to serve entanglement-based quantum protocols of which the real-world success or high-quality implementation relies on the longevity of entanglement in two-particle or multi-particle quantum states.