On the fidelity estimation for Entanglement Distribution Protocols

The distribution of entangled qubits over a noisy quantum channel and its evaluation with a quality metric as the fidelity is a key enabler of future quantum internet. We use a noisy entanglement pair generator providing pairs with dynamic fidelity. Furthermore, we model and implement the quantum channel as a rotational gate which negatively affects the distributed pair’s fidelity over time. Thus, forcing favourable and non-favourable times for the distribution of entanglement in terms of its fidelity. In this dynamic context, the entangled qubits are sequentially generated and distributed, revealing a frame with a certain number of distributed entangled pairs. A frame’s associated fidelity is fundamental to assessing the quality of the distributed pairs. It is computed by measuring a subset of the frame’s entangled pairs; therefore implying an overhead and leaving an effective payload of distributed entangled pairs. Additionally, the accuracy of the estimated frame’s fidelity depends on the amount of measured entangled pairs implying a trade-off between overhead and accuracy. In this work, we analyze the distribution of entanglement for the proposed dynamics by estimating the associated fidelity of frames with varying lengths at different operational points.