The rapid progress quantum devices have made in recent years has led to the need for systems that bridge the gap between quantum algorithms and quantum hardware. To this purpose different full-stack quantum programming platforms have been developed, providing high level languages for expressing quantum algorithms and providing compilers for making those quantum algorithms executable on a given quantum device. OpenQL is one such a platform, with support for compiling a variety of quantum program inputs into a quantum circuit, ready to be executed on the targeted quantum hardware. OpenQL is an evolving tool in which new features are constantly added to improve its performance and extend its functionality. In order to enhance OpenQL and provide some extra support to the researchers using OpenQL for their experiments, a visualization tool with three main functionalities has been developed in this thesis project. First, a circuit visualizer, with support for both visualizing the circuit output of the OpenQL compiler as an abstract gate representation and a pulse representation, which has been made specifically for quantum hardware running on superconducting qubits. Secondly, a mapping graph visualizer, which allows displaying the logical to physical qubit mapping per program cycle. And lastly a qubit interaction graph generator, which shows the required interactions between qubits of a given quantum algorithm.

The goal of this thesis is the design and development of the QuTech Central Controller, a system conceived to serve as the hardware/software interface of a quantum computer. This system represents an evolution of the QuMA microarchitecture to control a Surface-17 superconducting quantum processor, even though several architectural mechanisms are used to ensure the compatibility of the design with different quantum hardware technologies. In addition to an expansion of the control microarchitecture, the QuTech Central Controller represents an evolution of the overall system architecture, making use of a different hardware infrastructure to overcome previous scalability limitations.

The main contributions of this thesis are a proposed centralized microarchitecture capable of controlling up to 17 qubits, the implementation of this microarchitecture in a device called the QuTech Central Controller and its testing in dynamic quantum information processing experiments with superconducting qubits.

The quest to design a realizable quantum computer is a dream for many for the past few decades. At the moment, one of the promising designs is the transmon qubit, which is a superconducting qubit is the focus of this work. In order to analyze and design different components of a quantum chip, an understanding of the circuitry is required. By varying the circuit parameters, one can design the system according to requirements by constructing the required physical geometry that incorporates the design parameters. In this thesis work, part of the focus was to understand the transmon qubit circuit parameters, extract the circuit parameters such as capacitances from a physical geometry, build analytic and numerical 3D FEM models. Using a circuit model of the qubit system, the interdependence of the resonators that connects qubits with each other can be studied. Their resonances play a role in the qubit Hamiltonian and can be estimated by constructing accurate simulation models. This problem statement has been dealt with in the thesis work by constructing a hybrid circuitry of standard circuit components and 3D FEM simulated qubit unit cells. The quality factor of the measurement readout resonator of a qubit system needs to be characterized in a qubit system in order to target the rate and resolution at which the measurements can be done. In order to do so, the circuit parameters that affect the quality factor needs to be investigated. This problem statement has also been treated in this work.

Sub-mm astronomy in space calls for an array of photon noise limited detectors, both for imaging and broadband spectroscopy. Microwave Kinetic Inductance Detectors (MKIDs), superconducting resonance circuits, are a suitable candidate for this purpose due to its multiplexing potential, but in literature excess noise in phase readout is encountered and attributed to so-called two-level systems (TLSs). Reduction in TLS induced noise and loss will provide greater flexibility in design and a route towards background limited detector performance.
In this thesis, TLSs from surface and bulk sources are modelled, so that their behaviour can be predicted through numerical computations of the field distributions inside the resonators. These calculations not only provide a guide for sensible chip designs, but allow for interpretation of experimental data and determination of dominant TLS sources.
It is found that for Al CPW resonators on Si or SiN, the noise is surface dominated but with a non-negligible bulk contribution, while for microstrips on a SiN membrane, the noise is bulk dominated. As the loss in microstrips for narrow microstrips is dominated by the substrate-air interface, the dominant TLS loss and noise sources do not necessarily coincide and should be treated independently. This makes it impossible to determine the dominant CPW surface noise contribution. Additionally, microstrips and CPWs on the same dielectric perform similarly, while Si is better than SiN, both in terms of loss and noise, due to a combination of SiN interface and bulk effects. Finally, material dependent loss and noise parameters have been determined and the importance of thorough Si surface cleaning has been established, yielding the best Al CPW noise ever encountered.
For sub-mm astronomy in space, the logical path to improvement would be the use of thorough cleaned Si as a dielectric, overetching and the use of LEKIDS and hybrid resonators, where microstrips are still viable for use. Importantly, having located the important TLS locations for various cases, tackling these problems areas further could provide the step towards background limited performance in space.