Framework for Enhancing Quantum Network Performance Through Entanglement Buffering

Quantum networks rely on high-quality entangled pairs of qubits, known as entangled links, distributed across distant nodes. A recent paper by Bethany Davies, Álvaro G. Iñesta, and Stephanie Wehner introduces a framework to analyze the performance of entanglement buffering setups, which combine entanglement consumption, decoherence, and entanglement purification . The study proposes two key metrics: the availability, which is the steady-state probability that an entangled link is present, and the average consumed fidelity, which quantifies the steady-state quality of consumed links .

The researchers investigated a two-node system where each node has two quantum memories: one for long-term entanglement storage and another for entanglement generation. They modeled this setup as a continuous-time stochastic process and derived analytical expressions for the performance metrics. The findings reveal a trade-off between the availability and the average consumed fidelity .

The study also bounds these performance metrics for a buffering system using bilocal Clifford purification protocols. The analysis demonstrates that consistently purifying the buffered entanglement increases the average consumed fidelity, even when some buffered entanglement is discarded due to purification failures . This research provides valuable insights into maintaining high-quality entangled links in quantum networks, which is crucial for the development of robust quantum communication systems.