Closing the video series of operations on superconducting qubits, Adriaan Rol will tell you more about two qubit gates.

Main takeaways

• In transmon qubits, a the two qubit CPhase- or CZ-gate is used to form the universal gate set, which is implemented by tuning in and out of resonance with an interaction in the two-excitation manifold.
• The qubit-qubit coupling in transmons is mediated through a coupling resonator allowing convenient physical separation between qubits.
• Applying a current to the flux-bias line, the flux through the SQUID loop of the transmon changes allowing control of the qubit’s frequency.
• To avoid energy transfer to undesired states, a fast-adiabatic pulse that minimizes leakage is used.
• The key challenge in flux-pulsing based CZ-gates is correcting for distortions caused by electrical components in the signal path between the wave generator and the qubits.