Temporal Asymmetry in Entanglement Distillation

Entanglement, while central to quantum technologies, suffers from fragility when exposed to realistic noise. Conventional entanglement distillation tackles this by treating the noisy outputs of an entangling channel as static resources, applying local operations and classical communication after the fact. We challenge this static view. Our approach considers the entangling channel itself as a dynamic, consumable resource, actively purifying it by interposing optimally tailored local unitaries before the channel. We prove that preprocessing achieves entanglement fidelities fundamentally unreachable by any free postprocessing, exposing an intrinsic temporal asymmetry in distillation. Our experimental demonstration not only confirms these findings but also shows that preprocessing can elevate teleportation beyond the classical limit. By integrating theoretical framework with experimental realization, this Letter emphasizes the importance of embracing entanglement's dynamic nature, paving a more efficient path for optimizing quantum information processing.