Memory Decoherence-Aware Entanglement Purification in Quantum Communication Networks

Distributing entanglement in quantum repeater networks with sufficiently high fidelity is required to support applications such as quantum teleportation, distributed quantum computation, or quantum sensing. Early realizations of quantum repeater network architectures are not likely to support quantum error correction, and the speed of entanglement distribution will be limited by classical communication latency. Fidelity of distributed entanglement will be therefore susceptible to degradation due to memory decoherence. To address this problem, some previous studies considered re-initializing quantum memories after a predetermined amount of time. However, with this approach it is only possible to distribute entanglement with fidelity below the fidelity of newly generated entangled states. This work uses analytical tools and simulation to evaluate the performance of entanglement purification in realistic scenarios. We consider entanglement purification based on recurrence protocols for non-independent and identically distributed state ensembles, and explore purification strategies that depend on the available quantum memory capacity and state fidelity. In this talk we present our theory and simulation results, for instance the potential fidelity advantage of wait-till-the-end strategy over purify-immediately strategy.