Transmon Qubit: Anharmonicity and Coupling Strategies

This lecture covers the energy levels and regimes of the Cooper pair box (CPB) and transmon qubit, highlighting differences in Josephson and charging energies. It explains the impact of gate voltage on inducing Cooper pairs and the Josephson coupling enabling pair hopping. The transmon regime's insensitivity to charge offset and anharmonicity reduction are discussed. The lecture also explores the coupling strategies for transmon qubits, including fixed and tunable coupling methods, and direct capacitive coupling. Requirements for quantum computing, such as high-fidelity single qubit operations and entanglement between qubits, are outlined.