Continuous Variable Quantum Networks: A Layer-Based Approach

Abstract

Quantum networks promise to enable many interesting applications including enhanced imaging, enhanced sensing, and provably secure communication. Similar to how the OSI model allows for different layers of classical networks to be abstracted apart from each other, in this dissertation I present analogous layer boundaries that may be drawn to distinguish the different aspects of quantum networks that will be needed to enable us to realize them. For the physical layer we discuss the foundational quantum optics necessary to create and share entanglement as well as some theoretical performance bounds on characterizing squeezed vacuum sources. Afterwards we look at experimental characterizations of both single-mode and two-mode squeezed vacuum sources, which play very important roles in most applications of continuous variable quantum information. Next, for the link layer we study how to quantify the amount of entanglement shared between two network users when using protocols that do not result in easy-to-use states. We then use these tools to analyze several repeater protocols, focusing on ones that utilize continuous variable entanglement sources. Lastly, for the network layer we begin by considering how the phenomenon of requests being ‘blocked’ in classical networks can be ported over to entanglement distribution requests. We then showcase methods for calculating the capacity region of a single quantum switch, as well as fundamental tradeoffs in the optimization of switch placement within a quantum network.