Degree

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Document Type

Dissertation

Abstract

Future quantum technologies such as quantum communication, quantum sensing, and distributed quantum computation, will rely on networks of shared entanglement between spatially separated nodes. Distributing entanglement between these nodes, especially over long distances, currently remains a challenge, due to limitations resulting from the fragility of quantum systems, such as photon losses, non-ideal measurements, and quantum memories with short coherence times. In the absence of full-scale fault-tolerant quantum error correction, which can in principle overcome these limitations, we should understand the extent to which we can circumvent these limitations. In this work, we provide improved protocols and policies for entanglement distribution for terrestrial and hybrid satellite-ground based quantum networks. We study homogeneous and inhomogeneous networks, and networks with static and dynamic topologies, at the same time, taking practical limitations into account. Apart from analytical results, many numerical and simulation tools have been developed in this work that utilize both traditional methods such as Monte-Carlo and modern concepts like reinforcement learning algorithms.

In the first part of this work, focussed on linear repeater chains, we find policies that outperform the well-known and widely studied policies, such as swap-as-soon-as-possible and nested purification-doubling in practically relevant parameter regimes. We also carefully examine the role of entanglement distillation and include classical communication overheads into our models and simulations. In the next half of this work we will discuss satellite to ground and satellite to satellite entanglement distribution scenarios and different applications that utilize them, such as quantum clock synchronization, quantum key distribution and quantum networks. We will also quantify the coverage areas and the quality of the service available on Earth via satellite constellations carrying entanglement distribution sources.

Date

7-6-2024

Committee Chair

Hwang Lee

DOI

https://doi.org/10.31390/gradschool_dissertations.6541

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