Quantum entanglement serves as a valuable resource for many important quantumoperations. A pair of entangled qubits can be shared between two agents byfirst preparing a maximally entangled qubit pair at one agent, and then sendingone of the qubits to the other agent through a quantum channel. In thisprocess, the deterioration of entanglement is inevitable since the noiseinherent in the channel contaminates the qubit. To address this challenge,various quantum entanglement distillation (QED) algorithms have been developed.Among them, recurrence algorithms have advantages in terms of implementabilityand robustness. However, the efficiency of recurrence QED algorithms has notbeen investigated thoroughly in the literature. This paper put forth tworecurrence QED algorithms that adapt to the quantum channel to tackle theefficiency issue. The proposed algorithms have guaranteed convergence forquantum channels with two Kraus operators, which include phase-damping andamplitude-damping channels. Analytical results show that the convergence speedof these algorithms is improved from linear to quadratic and one of thealgorithms achieves the optimal speed. Numerical results confirm that theproposed algorithms significantly improve the efficiency of QED.
展开▼
