A Josephson junction is a device where a thin insulating barrier or a nanostructure is placed between two superconducting leads. Such a junction is essential to superconducting qubits that store... Show moreA Josephson junction is a device where a thin insulating barrier or a nanostructure is placed between two superconducting leads. Such a junction is essential to superconducting qubits that store quantum information due to its anharmonic spectrum. Therefore, understanding the physics of these junctions is crucial for predictions of the qubit's main qualities, such as the dephasing and relaxation time. Most modern superconducting qubits use Josephson junctions with an insulating barrier (tunneling junction). One of this thesis aims is to explore other possibilities that may allow for better properties of the qubit. Show less