arXiv subjects

Yuan Lee

Publications and source records attributed to Yuan Lee.

3 recordsLinked to original sources

arXiv2023

Zero-Added-Loss Entangled Photon Multiplexing for Ground- and Space-Based Quantum Networks

We propose a scheme for optical entanglement distribution in quantum networks based on a quasi-deterministic entangled photon pair source. By combining heralded photonic Bell pair generation with spectral mode conversion to interface with quantum memories, the scheme eliminates switching losses due to multiplexing. We analyze this `zero-added-loss multiplexing' (ZALM) Bell pair source for the particularly challenging problem of long-baseline entanglement distribution via satellites and ground-based memories, where it unlocks additional advantages: (i) the substantially higher channel efficiency $η$ of \textit{downlinks} vs.\ \textit{uplinks} with realistic adaptive optics, and (ii) photon loss occurring \textit{before} interaction with the quantum memory -- i.e., Alice and Bob receiving rather than transmitting -- improve entanglement generation rate scaling by $\mathcal{O}(\sqrtη)$. Based on numerical analyses, we estimate our protocol to achieve $>$10$~$ebits/s at memory multiplexing of $10^2$ spin qubits for ground distance $>$10$^2~$km, with the spin-spin Bell state fidelity exceeding 99$\%$. Our architecture presents a blueprint for realizing global-scale quantum networks in the near-term.

quant-ph↗

arXiv2022

A Quantum Router Architecture for High-Fidelity Entanglement Flows in Quantum Networks

The past decade has seen tremendous progress in experimentally realizing the building blocks of quantum repeaters. Repeater architectures with multiplexed quantum memories have been proposed to increase entanglement distribution rates, but an open challenge is to maintain entanglement fidelity over long-distance links. Here, we address this with a quantum router architecture comprising many quantum memories connected in a photonic switchboard to broker entanglement flows across quantum networks. We compute the rate and fidelity of entanglement distribution under this architecture using an event-based simulator, finding that the router improves the entanglement fidelity as multiplexing depth increases without a significant drop in the entanglement distribution rate. Specifically, the router permits channel-loss-invariant fidelity, i.e. the same fidelity achievable with lossless links. Furthermore, this scheme automatically prioritizes entanglement flows across the full network without requiring global network information. The proposed architecture uses present-day photonic technology, opening a path to near-term deployable multi-node quantum networks.

quant-ph↗

arXiv2022

Quantum Network Utility: A Framework for Benchmarking Quantum Networks

The absence of a common framework for benchmarking quantum networks is an obstacle to comparing the capabilities of different quantum networks. We propose a general framework for quantifying the performance of a quantum network, which is based on the value created by connecting users through quantum channels. In this framework, we define the quantum network utility metric $U_{QN}$ to capture the social and economic value of quantum networks. While the quantum network utility captures a variety of applications from secure communications to distributed sensing, we study the example of distributed quantum computing in detail. We hope that the adoption of the utility-based framework will serve as a foundation for guiding and assessing the development of new quantum network technologies and designs.

quant-ph↗