Integrating Normal-Metal Components into the Framework of Circuit Quantum Electrodynamics

Superconducting quantum bits are one of the leading frontrunners in the race to build a solid-state quantum computer. In circuit quantum electrodynamics (cQED), electronic quantum circuits, playing the role of quantum bits, qubits, are placed into superconducting cavities with incredibly weak dissipation. The resulting system exhibits both photon and qubit characteristics, and it is possible to perform complex operations by driving the system with microwaves. Progress has been rapid, with vast improvements in cavities, qubits, and in controlling the interaction between the two. As a result, the first simple quantum algorithms to utilize this architecture have recently been implemented. At the same time, there have been significant developments in improving our understanding of the heat flow in nanoelectronics. In particular the development of tunnel junctions has reached such a level, that it is now possible to control and measure the temperature of small metal islands with high precision. Such techniques have enabled the first observations of quantum-limited heat conduction through the photonic modes of a circuit. This thesis introduces some of the benefits that come with the unification of these two fields. Theoretical models for experiments in a superconducting cavity are presented, with heat conduction due to individual cavity photons discussed in detail, along with a novel method to vary the lifetime of a qubit over many orders of magnitude. The realisation of these experiments would be the first steps on the road to integrating normal-metal components with cQED.