Fig. 1: Device concept and design.
From: Large flux-mediated coupling in hybrid electromechanical system with a transmon qubit
a A schematic showing various components of the hybrid electromechanical system. The transmon qubit couples to an electromagnetic cavity via the transverse coupling. A low-frequency mechanical resonator couples to the transmon qubit via the longitudinal coupling. b A schematic of the SQUID loop with a suspended arm. Due to the magnetic flux Φ(x) dependence of Josephson inductance, it forms a displacement-dependent inductor. c A cross-sectional view of a 3D-cavity based transmon device. The gray (white) portion represents the copper (machined chamber). Input–output ports for microwave and a third port added for mechanical actuation is shown. The SQUID loop is placed inside a small recess of the cavity schematically shown by the lighter gray area. d A false-color scanning electron microscope image of the SQUID loop, showing the suspended portion of the Josephson junctions and the nanobeam. The mechanical resonator has a length and width of 45 μm and 300 nm, respectively. It consists of a 50-nm coating of aluminum over a 100-nm-thick highly stressed SiN film. The T-shaped electrode in the lower-half of the image is used to actuate the mechanical resonator.
