Tunable coupling between Xmon qubit and coplanar waveguide resonator

Realization of a flexible and tunable coupling scheme among qubits is critical for scalable quantum information processing. Here, we design and characterize a tunable coupling element based on Josephson junction, which can be adapted to an all-to-all connected circuit architecture where multiple Xmon qubits couple to a common coplanar waveguide resonator. The coupling strength is experimentally verified to be adjustable from 0 MHz to about 40 MHz, and the qubit lifetime can still be up to $12\mu s$ in the presence of the coupling element. (paper)