A test suite for quantum networks: Assessing an application’s effectiveness as a benchmark for quantum networks

In the development of any new technology, it is essential to have methods to assess the quality of a system, to compare different systems to one another, and to compare different versions of the same system, to see if changes to the system can actually be classified as improvements. For quantum networks, this is no different. To further develop...

A test suite for quantum network applications: Quantifying an application's ability to benchmark a quantum network

Quantum networks provide numerous potential benefits over classical networks, such as enhanced security and faster computation, making their further development a lucrative prospect. As is the case with any technology, the advancement of quantum networks relies on the development of frameworks to test their quality, and compare different...

Evaluating an RCPSP Implementation of Quantum Program Scheduling

The goal of quantum application scheduling is to enable the execution of applications on a quantum network. As the final step in the application scheduling process, program scheduling locally schedules execution of blocks of instructions on each node by defining so-called node schedules. In this thesis, we present a formal definition of program...

Microwave-Optics Entanglement Via Cavity Optomagnomechanics

Microwave-optics entanglement is a vital component for building hybrid quantum networks. Here, a new mechanism for preparing stationary entanglement between microwave and optical cavity fields in a cavity optomagnomechanical system is proposed. It consists of a magnon mode in a ferrimagnetic crystal that couples directly to a microwave cavity...

Entangling remote qubits using the single-photon protocol: an in-depth theoretical and experimental study

The generation of entanglement between remote matter qubits has developed into a key capability for fundamental investigations as well as for emerging quantum technologies. In the single-photon, protocol entanglement is heralded by generation of qubit-photon entangled states and subsequent detection of a single photon behind a beam splitter....

Integration and Collaboration in the Development of Quantum Technology: Development of the Physical Layer of a Quantum Network Stack integrated with the Link Layer - A Vision on University-Industry Collaborations in the Field of Quantum Technology Development

Throughout the work, the goal was to develop the physical layer of a quantum network stack. The layer of the network stack connected to the physical layer is the link layer. For entanglement-based quantum networks, we demonstrated the successful operation of a link layer and a physical layer. The physical layer’s entanglement generation...

Distributing entanglement in quantum networks

The research presented in this thesis focused on the problem of entanglement distribution. Simply put, the two main problems facing (practical) implementation of entanglement distribution over quantum networks are loss and noise. Quantum repeaters are meant to overcome the effects of loss, but in practice their implementation always comes at the...

Analysing the Effect of Asymmetry on the Performance of Atomic Ensemble Based Repeater Protocols

There has been a lot of research focused on the next generation of the internet, the so-called quantum networks. This analysis has been so far limited to mostly symmetrical architectures, but any near-term realisations of quantum networks using existing fibre topologies will contain asymmetry. In this thesis, we investigate how midpoint...

Entanglement Generation in Quantum Networks: Towards a universal and scalable quantum internet

Quantum mechanics shows that if one is able to generate and manipulate entanglement over a distance, one is able to perform certain tasks which are impossible using only classical communication. Classical communication refers to what is used in the Internet of today. A quantum internet would therefore bring new capabilities to our highly...

Quantum resource-saving protocols for early quantum networks

The Internet as we know it has had an immense impact on the way we communicate. We can now do it faster and more securely than ever before. Enabling quantum communication between any two points on Earth is the next step towards even more secure communication. This is the goal of the quantum internet. Although it is hard to predict all of the...

Simulation Model for Atomic Ensemble based Quantum Repeaters and the Optimization of their Positioning

The quantum internet will allow for communication via qubits, enabling for improved clock synchronization, blind quantum computing and quantum key distribution. Key components of such a quantum network are quantum repeaters, which help to overcome the exponential loss of photons in optical fibers. In this thesis we focus on one type of quantum...

Designing a quantum network protocol

The second quantum revolution brings with it the promise of a quantum internet. As the first quantum network hardware prototypes near completion new challenges emerge. A functional network is more than just the physical hardware, yet work on scalable quantum network systems is in its infancy. In this paper we present a quantum network protocol...

Parameter regimes for a single sequential quantum repeater

Quantum key distribution allows for the generation of a secret key between distant parties connected by a quantum channel such as optical fibre or free space. Unfortunately, the rate of generation of a secret key by direct transmission is fundamentally limited by the distance. This limit can be overcome by the implementation of so-called...

Optimal design of diamond-air microcavities for quantum networks using an analytical approach

Defect centres in diamond are promising building blocks for quantum networks thanks to a long-lived spin state and bright spin-photon interface. However, their low fraction of emission into a desired optical mode limits the entangling success probability. The key to overcoming this is through Purcell enhancement of the emission. Open Fabry...

Multiplexed entanglement generation over quantum networks using multi-qubit nodes

Quantum networks distributed over distances greater than a few kilometres will be limited by the time required for information to propagate between nodes. We analyse protocols that are able to circumvent this bottleneck by employing multi-qubit nodes and multiplexing. For each protocol, we investigate the key network parameters that determine...

Asynchronous reference frame agreement in a quantum network

An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised...

Shortcuts to Quantum Network Routing

Communication is a key part of society that we make huge investments in. Each message has to both arrive quickly and use minimal network resources. Moreover, communications must sometimes also remain private, so encryption is used to prevent third parties from listening in. However, standard classical encryption protocols are proven not to be...