Numerical simulations using COMSOL, of superconducting circuits for quantum information processing

This work is aimed at creating useful simulations to aid laboratory fabrication of superconducting qubits. First we make a description of the physics involved in superconducting qubit state preparation and control. Superconducting qubits are coupled and controlled via superconducting microwave transmission lines. Through the numerical simulation software COMSOL multiphysics, we aim at designing superconducting transmission lines, to attempt to gain insight on qubit cavity coupling. The interaction occurs via the vacuum state electric field E0 of cavity with island of superconducting material placed in it. This island is connected to the rest of the circuit using Josephson Junctions. These special connections can be described as a quantum anharmonic oscillators. This kind of system is of special interest to Quantum Computing, as this serves as a scalable quantum chips. Furthermore Josephson Junctions are incredibly rich objects, phenomenologically speaking. Having a wide range of applicability from academic research to industrial purposes. With emphasis on the known uses of Josephson Junctions such as highly sensitive metrology devices, rapid single flux quantum digital electronics and quantum-mechanical circuits. In the light of these significant applicabilities, the main purpose of this work is to decide if COMSOL Multiphysics is an appropriate tool to set a north for the creation of superconducting qubits. Since this is a preliminary study, we aim to bring to surface the underlying mechanisms that drive superconducting qubits. Therefore, we will simulate known Superconducting circuits, as opposed to making a hypothetical model. A simulation is not the real experiment. If it was possible to recreate the experiment to its full extent, the experiment itself would turn obsolete. Thus the structure of this work begins by trying to elucidate the basic principles behind the overall physics processes. In the following chapter, we describe some possible simulation setups. We conclude by contrasting our results to the available experimental data.