Cooper Pair Box and Transmon Regimes

This lecture covers the energy levels and properties of the Cooper Pair Box (CPB) and the Transmon qubit, focusing on the different regimes of Josephson and charging energies used. It explains the two-state approximation, the tuning of Josephson energy, and the impact of gate charge on the energy spectrum. The lecture also discusses the design and fabrication of the Transmon qubit, its reduced sensitivity to gate charge, and the use of magnetic flux for tuning. Additionally, it explores the dispersion and anharmonicity of the Transmon qubit, highlighting its good coherence and simple design, making it the main platform for superconducting quantum processors.