2023-11-30 13:00:00 | America/New_York

Stav Haldar Louisiana State University

Policies for multiplexed quantum repeaters

In this talk I will discuss some practical multiplexing-based policies for long-distance entanglement distribution in quantum networks. We propose two paradigmatic policies namely farthest neighbour swap-asap and strongest neighbour swap-asap, adapting swap as soon as policies for multiplexing based networks. We have benchmarked these policies against their non-multiplexed analogue which is a parallel swap-asap policy and a random-ranking multiplexed policy. We show that multiplexed policies yield a considerable advantage both in terms of reducing the average waiting time for end-to-end connectivity and increasing the fidelity of the end-to-end link. Further, an important consideration for practical and scalable implementation of entanglement distribution policies are their classical communication (CC) costs. Here we have considered these overheads and shown than quasi-local multiplexed policies ---using some but not all global knowledge of the network state--- do retain their advantage over non-multiplexed/random versions and completely local policies when CC costs are included. We also show the interplay of this advantage with the increasing size of the network (number of nodes), and extent of global knowledge utilized by the policy. Our results show that utilizing knowledge of the network state can enhance network outcomes even when the CC costs associated with such knowledge are accounted for. This is a very important conclusion from the point of view determining useful policies beyond the fully-local ones like swap-asap, especially for large quantum networks and achieving reasonable figures of merit for near-term and current quantum network realizations. To make this more quantitative, we give network outcomes for two concrete memory platforms namely rare-earth ion and diamond-vacancy based quantum memories, using multiplexing based policies.

Speaker's Bio

I am a graduate student in the Department of Physics and Astronomy at Louisiana State University working on theory and simulation of terrestrial and space-based quantum networks. My other research interests include critical phenomena and dynamics of many-body quantum systems, quantum optics and its interplay with gravity, and interferometry utilizing non-classical states of light.