Progress of coupled superconducting qubits

Quantum system based on superconducting circuit is considered as one of the most promising schemes to realize quantum computers due to its controllability, low dissipation and scalability. To implement large scale quantum computation, coherent coupling between qubits is crucial for controlling and transferring quantum states. In this review paper, we summarize the progress of coupled superconducting qubits, including local coupling via capacitance or inductance, multiple qubits coherent interaction through one-dimensional resonator as circuit quantum electrodynamics, and superconducting qubits in a three-dimensional waveguide cavity. Hamiltonians of various coupling schemes are analyzed and classification of these coupling structures is summarized based on the coupling range and tunability.